forked from AFPy/python-docs-fr
2743 lines
111 KiB
Plaintext
2743 lines
111 KiB
Plaintext
# SOME DESCRIPTIVE TITLE.
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# Copyright (C) 1990-2016, Python Software Foundation
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# This file is distributed under the same license as the Python package.
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# FIRST AUTHOR <EMAIL@ADDRESS>, YEAR.
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#
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#, fuzzy
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msgid ""
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msgstr ""
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"Project-Id-Version: Python 2.7\n"
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"Report-Msgid-Bugs-To: \n"
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"POT-Creation-Date: 2016-10-30 10:44+0100\n"
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"PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
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"Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
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"Language-Team: LANGUAGE <LL@li.org>\n"
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"MIME-Version: 1.0\n"
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"Content-Type: text/plain; charset=UTF-8\n"
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"Content-Transfer-Encoding: 8bit\n"
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#: ../Doc/reference/datamodel.rst:6
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msgid "Data model"
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msgstr ""
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#: ../Doc/reference/datamodel.rst:12
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msgid "Objects, values and types"
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msgstr ""
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#: ../Doc/reference/datamodel.rst:18
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msgid ""
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":dfn:`Objects` are Python's abstraction for data. All data in a Python "
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"program is represented by objects or by relations between objects. (In a "
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"sense, and in conformance to Von Neumann's model of a \"stored program "
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"computer,\" code is also represented by objects.)"
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msgstr ""
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#: ../Doc/reference/datamodel.rst:32
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msgid ""
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"Every object has an identity, a type and a value. An object's *identity* "
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"never changes once it has been created; you may think of it as the object's "
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"address in memory. The ':keyword:`is`' operator compares the identity of "
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"two objects; the :func:`id` function returns an integer representing its "
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"identity (currently implemented as its address). An object's :dfn:`type` is "
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"also unchangeable. [#]_ An object's type determines the operations that the "
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"object supports (e.g., \"does it have a length?\") and also defines the "
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"possible values for objects of that type. The :func:`type` function returns "
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"an object's type (which is an object itself). The *value* of some objects "
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"can change. Objects whose value can change are said to be *mutable*; "
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"objects whose value is unchangeable once they are created are called "
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"*immutable*. (The value of an immutable container object that contains a "
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"reference to a mutable object can change when the latter's value is changed; "
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"however the container is still considered immutable, because the collection "
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"of objects it contains cannot be changed. So, immutability is not strictly "
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"the same as having an unchangeable value, it is more subtle.) An object's "
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"mutability is determined by its type; for instance, numbers, strings and "
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"tuples are immutable, while dictionaries and lists are mutable."
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msgstr ""
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#: ../Doc/reference/datamodel.rst:55
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msgid ""
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"Objects are never explicitly destroyed; however, when they become "
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"unreachable they may be garbage-collected. An implementation is allowed to "
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"postpone garbage collection or omit it altogether --- it is a matter of "
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"implementation quality how garbage collection is implemented, as long as no "
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"objects are collected that are still reachable."
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msgstr ""
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#: ../Doc/reference/datamodel.rst:63
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msgid ""
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"CPython currently uses a reference-counting scheme with (optional) delayed "
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"detection of cyclically linked garbage, which collects most objects as soon "
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"as they become unreachable, but is not guaranteed to collect garbage "
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"containing circular references. See the documentation of the :mod:`gc` "
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"module for information on controlling the collection of cyclic garbage. "
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"Other implementations act differently and CPython may change. Do not depend "
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"on immediate finalization of objects when they become unreachable (ex: "
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"always close files)."
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msgstr ""
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#: ../Doc/reference/datamodel.rst:72
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msgid ""
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"Note that the use of the implementation's tracing or debugging facilities "
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"may keep objects alive that would normally be collectable. Also note that "
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"catching an exception with a ':keyword:`try`...\\ :keyword:`except`' "
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"statement may keep objects alive."
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msgstr ""
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#: ../Doc/reference/datamodel.rst:77
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msgid ""
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"Some objects contain references to \"external\" resources such as open files "
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"or windows. It is understood that these resources are freed when the object "
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"is garbage-collected, but since garbage collection is not guaranteed to "
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"happen, such objects also provide an explicit way to release the external "
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"resource, usually a :meth:`close` method. Programs are strongly recommended "
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"to explicitly close such objects. The ':keyword:`try`...\\ :keyword:"
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"`finally`' statement provides a convenient way to do this."
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msgstr ""
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#: ../Doc/reference/datamodel.rst:87
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msgid ""
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"Some objects contain references to other objects; these are called "
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"*containers*. Examples of containers are tuples, lists and dictionaries. "
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"The references are part of a container's value. In most cases, when we talk "
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"about the value of a container, we imply the values, not the identities of "
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"the contained objects; however, when we talk about the mutability of a "
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"container, only the identities of the immediately contained objects are "
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"implied. So, if an immutable container (like a tuple) contains a reference "
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"to a mutable object, its value changes if that mutable object is changed."
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msgstr ""
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#: ../Doc/reference/datamodel.rst:96
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msgid ""
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"Types affect almost all aspects of object behavior. Even the importance of "
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"object identity is affected in some sense: for immutable types, operations "
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"that compute new values may actually return a reference to any existing "
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"object with the same type and value, while for mutable objects this is not "
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"allowed. E.g., after ``a = 1; b = 1``, ``a`` and ``b`` may or may not refer "
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"to the same object with the value one, depending on the implementation, but "
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"after ``c = []; d = []``, ``c`` and ``d`` are guaranteed to refer to two "
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"different, unique, newly created empty lists. (Note that ``c = d = []`` "
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"assigns the same object to both ``c`` and ``d``.)"
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msgstr ""
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#: ../Doc/reference/datamodel.rst:110
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msgid "The standard type hierarchy"
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msgstr ""
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#: ../Doc/reference/datamodel.rst:119
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msgid ""
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"Below is a list of the types that are built into Python. Extension modules "
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"(written in C, Java, or other languages, depending on the implementation) "
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"can define additional types. Future versions of Python may add types to the "
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"type hierarchy (e.g., rational numbers, efficiently stored arrays of "
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"integers, etc.)."
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msgstr ""
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#: ../Doc/reference/datamodel.rst:129
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msgid ""
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"Some of the type descriptions below contain a paragraph listing 'special "
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"attributes.' These are attributes that provide access to the implementation "
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"and are not intended for general use. Their definition may change in the "
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"future."
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msgstr ""
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#: ../Doc/reference/datamodel.rst:139
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msgid "None"
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msgstr ""
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#: ../Doc/reference/datamodel.rst:136
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msgid ""
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"This type has a single value. There is a single object with this value. "
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"This object is accessed through the built-in name ``None``. It is used to "
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"signify the absence of a value in many situations, e.g., it is returned from "
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"functions that don't explicitly return anything. Its truth value is false."
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msgstr ""
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#: ../Doc/reference/datamodel.rst:149
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msgid "NotImplemented"
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msgstr ""
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#: ../Doc/reference/datamodel.rst:144
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msgid ""
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"This type has a single value. There is a single object with this value. "
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"This object is accessed through the built-in name ``NotImplemented``. "
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"Numeric methods and rich comparison methods may return this value if they do "
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"not implement the operation for the operands provided. (The interpreter "
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"will then try the reflected operation, or some other fallback, depending on "
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"the operator.) Its truth value is true."
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msgstr ""
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#: ../Doc/reference/datamodel.rst:157
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msgid "Ellipsis"
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msgstr ""
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#: ../Doc/reference/datamodel.rst:154
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msgid ""
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"This type has a single value. There is a single object with this value. "
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"This object is accessed through the built-in name ``Ellipsis``. It is used "
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"to indicate the presence of the ``...`` syntax in a slice. Its truth value "
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"is true."
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msgstr ""
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#: ../Doc/reference/datamodel.rst:249
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msgid ":class:`numbers.Number`"
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msgstr ""
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#: ../Doc/reference/datamodel.rst:162
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msgid ""
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"These are created by numeric literals and returned as results by arithmetic "
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"operators and arithmetic built-in functions. Numeric objects are immutable; "
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"once created their value never changes. Python numbers are of course "
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"strongly related to mathematical numbers, but subject to the limitations of "
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"numerical representation in computers."
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msgstr ""
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#: ../Doc/reference/datamodel.rst:168
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msgid ""
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"Python distinguishes between integers, floating point numbers, and complex "
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"numbers:"
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msgstr ""
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#: ../Doc/reference/datamodel.rst:224
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msgid ":class:`numbers.Integral`"
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msgstr ""
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#: ../Doc/reference/datamodel.rst:174
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msgid ""
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"These represent elements from the mathematical set of integers (positive and "
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"negative)."
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msgstr ""
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#: ../Doc/reference/datamodel.rst:177
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msgid "There are three types of integers:"
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msgstr ""
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#: ../Doc/reference/datamodel.rst:192
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msgid "Plain integers"
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msgstr ""
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#: ../Doc/reference/datamodel.rst:184
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msgid ""
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"These represent numbers in the range -2147483648 through 2147483647. (The "
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"range may be larger on machines with a larger natural word size, but not "
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"smaller.) When the result of an operation would fall outside this range, "
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"the result is normally returned as a long integer (in some cases, the "
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"exception :exc:`OverflowError` is raised instead). For the purpose of shift "
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"and mask operations, integers are assumed to have a binary, 2's complement "
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"notation using 32 or more bits, and hiding no bits from the user (i.e., all "
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"4294967296 different bit patterns correspond to different values)."
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msgstr ""
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#: ../Doc/reference/datamodel.rst:201
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msgid "Long integers"
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msgstr ""
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#: ../Doc/reference/datamodel.rst:197
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msgid ""
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"These represent numbers in an unlimited range, subject to available "
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"(virtual) memory only. For the purpose of shift and mask operations, a "
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"binary representation is assumed, and negative numbers are represented in a "
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"variant of 2's complement which gives the illusion of an infinite string of "
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"sign bits extending to the left."
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msgstr ""
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#: ../Doc/reference/datamodel.rst:214
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msgid "Booleans"
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msgstr ""
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#: ../Doc/reference/datamodel.rst:209
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msgid ""
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"These represent the truth values False and True. The two objects "
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"representing the values ``False`` and ``True`` are the only Boolean objects. "
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"The Boolean type is a subtype of plain integers, and Boolean values behave "
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"like the values 0 and 1, respectively, in almost all contexts, the exception "
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"being that when converted to a string, the strings ``\"False\"`` or ``\"True"
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"\"`` are returned, respectively."
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msgstr ""
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#: ../Doc/reference/datamodel.rst:218
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msgid ""
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"The rules for integer representation are intended to give the most "
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"meaningful interpretation of shift and mask operations involving negative "
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"integers and the least surprises when switching between the plain and long "
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"integer domains. Any operation, if it yields a result in the plain integer "
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"domain, will yield the same result in the long integer domain or when using "
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"mixed operands. The switch between domains is transparent to the programmer."
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msgstr ""
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#: ../Doc/reference/datamodel.rst:239
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msgid ":class:`numbers.Real` (:class:`float`)"
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msgstr ""
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#: ../Doc/reference/datamodel.rst:233
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msgid ""
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"These represent machine-level double precision floating point numbers. You "
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"are at the mercy of the underlying machine architecture (and C or Java "
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"implementation) for the accepted range and handling of overflow. Python does "
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"not support single-precision floating point numbers; the savings in "
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"processor and memory usage that are usually the reason for using these are "
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"dwarfed by the overhead of using objects in Python, so there is no reason to "
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"complicate the language with two kinds of floating point numbers."
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msgstr ""
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#: ../Doc/reference/datamodel.rst:249
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msgid ":class:`numbers.Complex`"
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msgstr ""
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#: ../Doc/reference/datamodel.rst:246
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msgid ""
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"These represent complex numbers as a pair of machine-level double precision "
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"floating point numbers. The same caveats apply as for floating point "
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"numbers. The real and imaginary parts of a complex number ``z`` can be "
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"retrieved through the read-only attributes ``z.real`` and ``z.imag``."
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msgstr ""
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#: ../Doc/reference/datamodel.rst:386
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msgid "Sequences"
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msgstr ""
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#: ../Doc/reference/datamodel.rst:259
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msgid ""
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"These represent finite ordered sets indexed by non-negative numbers. The "
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"built-in function :func:`len` returns the number of items of a sequence. "
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"When the length of a sequence is *n*, the index set contains the numbers 0, "
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"1, ..., *n*-1. Item *i* of sequence *a* is selected by ``a[i]``."
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msgstr ""
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#: ../Doc/reference/datamodel.rst:266
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msgid ""
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"Sequences also support slicing: ``a[i:j]`` selects all items with index *k* "
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"such that *i* ``<=`` *k* ``<`` *j*. When used as an expression, a slice is "
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"a sequence of the same type. This implies that the index set is renumbered "
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"so that it starts at 0."
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msgstr ""
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#: ../Doc/reference/datamodel.rst:273
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msgid ""
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"Some sequences also support \"extended slicing\" with a third \"step\" "
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"parameter: ``a[i:j:k]`` selects all items of *a* with index *x* where ``x = "
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"i + n*k``, *n* ``>=`` ``0`` and *i* ``<=`` *x* ``<`` *j*."
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msgstr ""
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#: ../Doc/reference/datamodel.rst:277
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msgid "Sequences are distinguished according to their mutability:"
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msgstr ""
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#: ../Doc/reference/datamodel.rst:352
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msgid "Immutable sequences"
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msgstr ""
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#: ../Doc/reference/datamodel.rst:284
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msgid ""
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"An object of an immutable sequence type cannot change once it is created. "
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"(If the object contains references to other objects, these other objects may "
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"be mutable and may be changed; however, the collection of objects directly "
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"referenced by an immutable object cannot change.)"
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msgstr ""
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#: ../Doc/reference/datamodel.rst:289
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msgid "The following types are immutable sequences:"
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msgstr ""
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#: ../Doc/reference/datamodel.rst:319
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msgid "Strings"
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msgstr "Les chaînes de caractères"
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#: ../Doc/reference/datamodel.rst:300
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msgid ""
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"The items of a string are characters. There is no separate character type; "
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"a character is represented by a string of one item. Characters represent (at "
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"least) 8-bit bytes. The built-in functions :func:`chr` and :func:`ord` "
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"convert between characters and nonnegative integers representing the byte "
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"values. Bytes with the values 0-127 usually represent the corresponding "
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"ASCII values, but the interpretation of values is up to the program. The "
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"string data type is also used to represent arrays of bytes, e.g., to hold "
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"data read from a file."
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msgstr ""
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#: ../Doc/reference/datamodel.rst:316
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msgid ""
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"(On systems whose native character set is not ASCII, strings may use EBCDIC "
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"in their internal representation, provided the functions :func:`chr` and :"
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"func:`ord` implement a mapping between ASCII and EBCDIC, and string "
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"comparison preserves the ASCII order. Or perhaps someone can propose a "
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"better rule?)"
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msgstr ""
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#: ../Doc/reference/datamodel.rst:340
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msgid "Unicode"
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msgstr "Unicode"
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#: ../Doc/reference/datamodel.rst:331
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msgid ""
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"The items of a Unicode object are Unicode code units. A Unicode code unit "
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"is represented by a Unicode object of one item and can hold either a 16-bit "
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"or 32-bit value representing a Unicode ordinal (the maximum value for the "
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"ordinal is given in ``sys.maxunicode``, and depends on how Python is "
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"configured at compile time). Surrogate pairs may be present in the Unicode "
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"object, and will be reported as two separate items. The built-in functions :"
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"func:`unichr` and :func:`ord` convert between code units and nonnegative "
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"integers representing the Unicode ordinals as defined in the Unicode "
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"Standard 3.0. Conversion from and to other encodings are possible through "
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"the Unicode method :meth:`encode` and the built-in function :func:`unicode`."
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msgstr ""
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#: ../Doc/reference/datamodel.rst:352
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msgid "Tuples"
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msgstr "Tuples"
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#: ../Doc/reference/datamodel.rst:348
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msgid ""
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"The items of a tuple are arbitrary Python objects. Tuples of two or more "
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"items are formed by comma-separated lists of expressions. A tuple of one "
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"item (a 'singleton') can be formed by affixing a comma to an expression (an "
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"expression by itself does not create a tuple, since parentheses must be "
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"usable for grouping of expressions). An empty tuple can be formed by an "
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"empty pair of parentheses."
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msgstr ""
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#: ../Doc/reference/datamodel.rst:386
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msgid "Mutable sequences"
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msgstr ""
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#: ../Doc/reference/datamodel.rst:362
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msgid ""
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"Mutable sequences can be changed after they are created. The subscription "
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"and slicing notations can be used as the target of assignment and :keyword:"
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"`del` (delete) statements."
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msgstr ""
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#: ../Doc/reference/datamodel.rst:366
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msgid "There are currently two intrinsic mutable sequence types:"
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msgstr ""
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#: ../Doc/reference/datamodel.rst:373
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msgid "Lists"
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msgstr "Les listes"
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#: ../Doc/reference/datamodel.rst:371
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msgid ""
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"The items of a list are arbitrary Python objects. Lists are formed by "
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"placing a comma-separated list of expressions in square brackets. (Note that "
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"there are no special cases needed to form lists of length 0 or 1.)"
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msgstr ""
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#: ../Doc/reference/datamodel.rst:381
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msgid "Byte Arrays"
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msgstr ""
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#: ../Doc/reference/datamodel.rst:378
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msgid ""
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"A bytearray object is a mutable array. They are created by the built-in :"
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"func:`bytearray` constructor. Aside from being mutable (and hence "
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"unhashable), byte arrays otherwise provide the same interface and "
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"functionality as immutable bytes objects."
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msgstr ""
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#: ../Doc/reference/datamodel.rst:385
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msgid ""
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"The extension module :mod:`array` provides an additional example of a "
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"mutable sequence type."
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msgstr ""
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#: ../Doc/reference/datamodel.rst:420
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msgid "Set types"
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msgstr ""
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#: ../Doc/reference/datamodel.rst:393
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msgid ""
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"These represent unordered, finite sets of unique, immutable objects. As "
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"such, they cannot be indexed by any subscript. However, they can be iterated "
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"over, and the built-in function :func:`len` returns the number of items in a "
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"set. Common uses for sets are fast membership testing, removing duplicates "
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"from a sequence, and computing mathematical operations such as intersection, "
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"union, difference, and symmetric difference."
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msgstr ""
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#: ../Doc/reference/datamodel.rst:400
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msgid ""
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"For set elements, the same immutability rules apply as for dictionary keys. "
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"Note that numeric types obey the normal rules for numeric comparison: if two "
|
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"numbers compare equal (e.g., ``1`` and ``1.0``), only one of them can be "
|
|
"contained in a set."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:405
|
|
msgid "There are currently two intrinsic set types:"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:412
|
|
msgid "Sets"
|
|
msgstr "Les ensembles"
|
|
|
|
#: ../Doc/reference/datamodel.rst:410
|
|
msgid ""
|
|
"These represent a mutable set. They are created by the built-in :func:`set` "
|
|
"constructor and can be modified afterwards by several methods, such as :meth:"
|
|
"`~set.add`."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:420
|
|
msgid "Frozen sets"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:417
|
|
msgid ""
|
|
"These represent an immutable set. They are created by the built-in :func:"
|
|
"`frozenset` constructor. As a frozenset is immutable and :term:`hashable`, "
|
|
"it can be used again as an element of another set, or as a dictionary key."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:457
|
|
msgid "Mappings"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:428
|
|
msgid ""
|
|
"These represent finite sets of objects indexed by arbitrary index sets. The "
|
|
"subscript notation ``a[k]`` selects the item indexed by ``k`` from the "
|
|
"mapping ``a``; this can be used in expressions and as the target of "
|
|
"assignments or :keyword:`del` statements. The built-in function :func:`len` "
|
|
"returns the number of items in a mapping."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:434
|
|
msgid "There is currently a single intrinsic mapping type:"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:457
|
|
msgid "Dictionaries"
|
|
msgstr "Dictionnaires"
|
|
|
|
#: ../Doc/reference/datamodel.rst:439
|
|
msgid ""
|
|
"These represent finite sets of objects indexed by nearly arbitrary values. "
|
|
"The only types of values not acceptable as keys are values containing lists "
|
|
"or dictionaries or other mutable types that are compared by value rather "
|
|
"than by object identity, the reason being that the efficient implementation "
|
|
"of dictionaries requires a key's hash value to remain constant. Numeric "
|
|
"types used for keys obey the normal rules for numeric comparison: if two "
|
|
"numbers compare equal (e.g., ``1`` and ``1.0``) then they can be used "
|
|
"interchangeably to index the same dictionary entry."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:448
|
|
msgid ""
|
|
"Dictionaries are mutable; they can be created by the ``{...}`` notation (see "
|
|
"section :ref:`dict`)."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:456
|
|
msgid ""
|
|
"The extension modules :mod:`dbm`, :mod:`gdbm`, and :mod:`bsddb` provide "
|
|
"additional examples of mapping types."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:727
|
|
msgid "Callable types"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:466
|
|
msgid ""
|
|
"These are the types to which the function call operation (see section :ref:"
|
|
"`calls`) can be applied:"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:560
|
|
msgid "User-defined functions"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:475
|
|
msgid ""
|
|
"A user-defined function object is created by a function definition (see "
|
|
"section :ref:`function`). It should be called with an argument list "
|
|
"containing the same number of items as the function's formal parameter list."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:480
|
|
msgid "Special attributes:"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:503
|
|
msgid "Attribute"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:503
|
|
msgid "Meaning"
|
|
msgstr "Signification"
|
|
|
|
#: ../Doc/reference/datamodel.rst:505
|
|
msgid ":attr:`__doc__` :attr:`func_doc`"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:505
|
|
msgid "The function's documentation string, or ``None`` if unavailable."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:505 ../Doc/reference/datamodel.rst:509
|
|
#: ../Doc/reference/datamodel.rst:513 ../Doc/reference/datamodel.rst:517
|
|
#: ../Doc/reference/datamodel.rst:523 ../Doc/reference/datamodel.rst:533
|
|
msgid "Writable"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:509
|
|
msgid ":attr:`~definition.\\ __name__` :attr:`func_name`"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:509
|
|
msgid "The function's name"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:513
|
|
msgid ":attr:`__module__`"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:513
|
|
msgid ""
|
|
"The name of the module the function was defined in, or ``None`` if "
|
|
"unavailable."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:517
|
|
msgid ":attr:`__defaults__` :attr:`func_defaults`"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:517
|
|
msgid ""
|
|
"A tuple containing default argument values for those arguments that have "
|
|
"defaults, or ``None`` if no arguments have a default value."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:523
|
|
msgid ":attr:`__code__` :attr:`func_code`"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:523
|
|
msgid "The code object representing the compiled function body."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:526
|
|
msgid ":attr:`__globals__` :attr:`func_globals`"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:526
|
|
msgid ""
|
|
"A reference to the dictionary that holds the function's global variables --- "
|
|
"the global namespace of the module in which the function was defined."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:526 ../Doc/reference/datamodel.rst:537
|
|
msgid "Read-only"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:533
|
|
msgid ":attr:`~object.\\ __dict__` :attr:`func_dict`"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:533
|
|
msgid "The namespace supporting arbitrary function attributes."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:537
|
|
msgid ":attr:`__closure__` :attr:`func_closure`"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:537
|
|
msgid ""
|
|
"``None`` or a tuple of cells that contain bindings for the function's free "
|
|
"variables."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:542
|
|
msgid ""
|
|
"Most of the attributes labelled \"Writable\" check the type of the assigned "
|
|
"value."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:544
|
|
msgid "``func_name`` is now writable."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:547
|
|
msgid ""
|
|
"The double-underscore attributes ``__closure__``, ``__code__``, "
|
|
"``__defaults__``, and ``__globals__`` were introduced as aliases for the "
|
|
"corresponding ``func_*`` attributes for forwards compatibility with Python 3."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:553
|
|
msgid ""
|
|
"Function objects also support getting and setting arbitrary attributes, "
|
|
"which can be used, for example, to attach metadata to functions. Regular "
|
|
"attribute dot-notation is used to get and set such attributes. *Note that "
|
|
"the current implementation only supports function attributes on user-defined "
|
|
"functions. Function attributes on built-in functions may be supported in the "
|
|
"future.*"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:559
|
|
msgid ""
|
|
"Additional information about a function's definition can be retrieved from "
|
|
"its code object; see the description of internal types below."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:658
|
|
msgid "User-defined methods"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:568
|
|
msgid ""
|
|
"A user-defined method object combines a class, a class instance (or "
|
|
"``None``) and any callable object (normally a user-defined function)."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:571
|
|
msgid ""
|
|
"Special read-only attributes: :attr:`im_self` is the class instance object, :"
|
|
"attr:`im_func` is the function object; :attr:`im_class` is the class of :"
|
|
"attr:`im_self` for bound methods or the class that asked for the method for "
|
|
"unbound methods; :attr:`__doc__` is the method's documentation (same as "
|
|
"``im_func.__doc__``); :attr:`~definition.__name__` is the method name (same "
|
|
"as ``im_func.__name__``); :attr:`__module__` is the name of the module the "
|
|
"method was defined in, or ``None`` if unavailable."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:579
|
|
msgid ":attr:`im_self` used to refer to the class that defined the method."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:582
|
|
msgid ""
|
|
"For Python 3 forward-compatibility, :attr:`im_func` is also available as :"
|
|
"attr:`__func__`, and :attr:`im_self` as :attr:`__self__`."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:593
|
|
msgid ""
|
|
"Methods also support accessing (but not setting) the arbitrary function "
|
|
"attributes on the underlying function object."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:596
|
|
msgid ""
|
|
"User-defined method objects may be created when getting an attribute of a "
|
|
"class (perhaps via an instance of that class), if that attribute is a user-"
|
|
"defined function object, an unbound user-defined method object, or a class "
|
|
"method object. When the attribute is a user-defined method object, a new "
|
|
"method object is only created if the class from which it is being retrieved "
|
|
"is the same as, or a derived class of, the class stored in the original "
|
|
"method object; otherwise, the original method object is used as it is."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:609
|
|
msgid ""
|
|
"When a user-defined method object is created by retrieving a user-defined "
|
|
"function object from a class, its :attr:`im_self` attribute is ``None`` and "
|
|
"the method object is said to be unbound. When one is created by retrieving a "
|
|
"user-defined function object from a class via one of its instances, its :"
|
|
"attr:`im_self` attribute is the instance, and the method object is said to "
|
|
"be bound. In either case, the new method's :attr:`im_class` attribute is the "
|
|
"class from which the retrieval takes place, and its :attr:`im_func` "
|
|
"attribute is the original function object."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:620
|
|
msgid ""
|
|
"When a user-defined method object is created by retrieving another method "
|
|
"object from a class or instance, the behaviour is the same as for a function "
|
|
"object, except that the :attr:`im_func` attribute of the new instance is not "
|
|
"the original method object but its :attr:`im_func` attribute."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:630
|
|
msgid ""
|
|
"When a user-defined method object is created by retrieving a class method "
|
|
"object from a class or instance, its :attr:`im_self` attribute is the class "
|
|
"itself, and its :attr:`im_func` attribute is the function object underlying "
|
|
"the class method."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:634
|
|
msgid ""
|
|
"When an unbound user-defined method object is called, the underlying "
|
|
"function (:attr:`im_func`) is called, with the restriction that the first "
|
|
"argument must be an instance of the proper class (:attr:`im_class`) or of a "
|
|
"derived class thereof."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:639
|
|
msgid ""
|
|
"When a bound user-defined method object is called, the underlying function (:"
|
|
"attr:`im_func`) is called, inserting the class instance (:attr:`im_self`) in "
|
|
"front of the argument list. For instance, when :class:`C` is a class which "
|
|
"contains a definition for a function :meth:`f`, and ``x`` is an instance of :"
|
|
"class:`C`, calling ``x.f(1)`` is equivalent to calling ``C.f(x, 1)``."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:645
|
|
msgid ""
|
|
"When a user-defined method object is derived from a class method object, the "
|
|
"\"class instance\" stored in :attr:`im_self` will actually be the class "
|
|
"itself, so that calling either ``x.f(1)`` or ``C.f(1)`` is equivalent to "
|
|
"calling ``f(C,1)`` where ``f`` is the underlying function."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:650
|
|
msgid ""
|
|
"Note that the transformation from function object to (unbound or bound) "
|
|
"method object happens each time the attribute is retrieved from the class or "
|
|
"instance. In some cases, a fruitful optimization is to assign the attribute "
|
|
"to a local variable and call that local variable. Also notice that this "
|
|
"transformation only happens for user-defined functions; other callable "
|
|
"objects (and all non-callable objects) are retrieved without "
|
|
"transformation. It is also important to note that user-defined functions "
|
|
"which are attributes of a class instance are not converted to bound methods; "
|
|
"this *only* happens when the function is an attribute of the class."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:674
|
|
msgid "Generator functions"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:665
|
|
msgid ""
|
|
"A function or method which uses the :keyword:`yield` statement (see section :"
|
|
"ref:`yield`) is called a :dfn:`generator function`. Such a function, when "
|
|
"called, always returns an iterator object which can be used to execute the "
|
|
"body of the function: calling the iterator's :meth:`~iterator.next` method "
|
|
"will cause the function to execute until it provides a value using the :"
|
|
"keyword:`yield` statement. When the function executes a :keyword:`return` "
|
|
"statement or falls off the end, a :exc:`StopIteration` exception is raised "
|
|
"and the iterator will have reached the end of the set of values to be "
|
|
"returned."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:689
|
|
msgid "Built-in functions"
|
|
msgstr "Fonctions Natives"
|
|
|
|
#: ../Doc/reference/datamodel.rst:682
|
|
msgid ""
|
|
"A built-in function object is a wrapper around a C function. Examples of "
|
|
"built-in functions are :func:`len` and :func:`math.sin` (:mod:`math` is a "
|
|
"standard built-in module). The number and type of the arguments are "
|
|
"determined by the C function. Special read-only attributes: :attr:`__doc__` "
|
|
"is the function's documentation string, or ``None`` if unavailable; :attr:"
|
|
"`~definition.__name__` is the function's name; :attr:`__self__` is set to "
|
|
"``None`` (but see the next item); :attr:`__module__` is the name of the "
|
|
"module the function was defined in or ``None`` if unavailable."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:701
|
|
msgid "Built-in methods"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:697
|
|
msgid ""
|
|
"This is really a different disguise of a built-in function, this time "
|
|
"containing an object passed to the C function as an implicit extra "
|
|
"argument. An example of a built-in method is ``alist.append()``, assuming "
|
|
"*alist* is a list object. In this case, the special read-only attribute :"
|
|
"attr:`__self__` is set to the object denoted by *alist*."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:708
|
|
msgid "Class Types"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:704
|
|
msgid ""
|
|
"Class types, or \"new-style classes,\" are callable. These objects normally "
|
|
"act as factories for new instances of themselves, but variations are "
|
|
"possible for class types that override :meth:`__new__`. The arguments of "
|
|
"the call are passed to :meth:`__new__` and, in the typical case, to :meth:"
|
|
"`__init__` to initialize the new instance."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:722
|
|
msgid "Classic Classes"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:718
|
|
msgid ""
|
|
"Class objects are described below. When a class object is called, a new "
|
|
"class instance (also described below) is created and returned. This implies "
|
|
"a call to the class's :meth:`__init__` method if it has one. Any arguments "
|
|
"are passed on to the :meth:`__init__` method. If there is no :meth:"
|
|
"`__init__` method, the class must be called without arguments."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:727 ../Doc/reference/datamodel.rst:879
|
|
msgid "Class instances"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:725
|
|
msgid ""
|
|
"Class instances are described below. Class instances are callable only when "
|
|
"the class has a :meth:`__call__` method; ``x(arguments)`` is a shorthand for "
|
|
"``x.__call__(arguments)``."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:770
|
|
msgid "Modules"
|
|
msgstr "Modules"
|
|
|
|
#: ../Doc/reference/datamodel.rst:734
|
|
msgid ""
|
|
"Modules are imported by the :keyword:`import` statement (see section :ref:"
|
|
"`import`). A module object has a namespace implemented by a dictionary "
|
|
"object (this is the dictionary referenced by the func_globals attribute of "
|
|
"functions defined in the module). Attribute references are translated to "
|
|
"lookups in this dictionary, e.g., ``m.x`` is equivalent to ``m.__dict__[\"x"
|
|
"\"]``. A module object does not contain the code object used to initialize "
|
|
"the module (since it isn't needed once the initialization is done)."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:743
|
|
msgid ""
|
|
"Attribute assignment updates the module's namespace dictionary, e.g., ``m.x "
|
|
"= 1`` is equivalent to ``m.__dict__[\"x\"] = 1``."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:748
|
|
msgid ""
|
|
"Special read-only attribute: :attr:`~object.__dict__` is the module's "
|
|
"namespace as a dictionary object."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:753
|
|
msgid ""
|
|
"Because of the way CPython clears module dictionaries, the module dictionary "
|
|
"will be cleared when the module falls out of scope even if the dictionary "
|
|
"still has live references. To avoid this, copy the dictionary or keep the "
|
|
"module around while using its dictionary directly."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:764
|
|
msgid ""
|
|
"Predefined (writable) attributes: :attr:`__name__` is the module's name; :"
|
|
"attr:`__doc__` is the module's documentation string, or ``None`` if "
|
|
"unavailable; :attr:`__file__` is the pathname of the file from which the "
|
|
"module was loaded, if it was loaded from a file. The :attr:`__file__` "
|
|
"attribute is not present for C modules that are statically linked into the "
|
|
"interpreter; for extension modules loaded dynamically from a shared library, "
|
|
"it is the pathname of the shared library file."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:833
|
|
msgid "Classes"
|
|
msgstr "Classes"
|
|
|
|
#: ../Doc/reference/datamodel.rst:773
|
|
msgid ""
|
|
"Both class types (new-style classes) and class objects (old-style/classic "
|
|
"classes) are typically created by class definitions (see section :ref:"
|
|
"`class`). A class has a namespace implemented by a dictionary object. Class "
|
|
"attribute references are translated to lookups in this dictionary, e.g., ``C."
|
|
"x`` is translated to ``C.__dict__[\"x\"]`` (although for new-style classes "
|
|
"in particular there are a number of hooks which allow for other means of "
|
|
"locating attributes). When the attribute name is not found there, the "
|
|
"attribute search continues in the base classes. For old-style classes, the "
|
|
"search is depth-first, left-to-right in the order of occurrence in the base "
|
|
"class list. New-style classes use the more complex C3 method resolution "
|
|
"order which behaves correctly even in the presence of 'diamond' inheritance "
|
|
"structures where there are multiple inheritance paths leading back to a "
|
|
"common ancestor. Additional details on the C3 MRO used by new-style classes "
|
|
"can be found in the documentation accompanying the 2.3 release at https://"
|
|
"www.python.org/download/releases/2.3/mro/."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:800
|
|
msgid ""
|
|
"When a class attribute reference (for class :class:`C`, say) would yield a "
|
|
"user-defined function object or an unbound user-defined method object whose "
|
|
"associated class is either :class:`C` or one of its base classes, it is "
|
|
"transformed into an unbound user-defined method object whose :attr:"
|
|
"`im_class` attribute is :class:`C`. When it would yield a class method "
|
|
"object, it is transformed into a bound user-defined method object whose :"
|
|
"attr:`im_self` attribute is :class:`C`. When it would yield a static method "
|
|
"object, it is transformed into the object wrapped by the static method "
|
|
"object. See section :ref:`descriptors` for another way in which attributes "
|
|
"retrieved from a class may differ from those actually contained in its :attr:"
|
|
"`~object.__dict__` (note that only new-style classes support descriptors)."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:814
|
|
msgid ""
|
|
"Class attribute assignments update the class's dictionary, never the "
|
|
"dictionary of a base class."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:819
|
|
msgid ""
|
|
"A class object can be called (see above) to yield a class instance (see "
|
|
"below)."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:828
|
|
msgid ""
|
|
"Special attributes: :attr:`~definition.__name__` is the class name; :attr:"
|
|
"`__module__` is the module name in which the class was defined; :attr:"
|
|
"`~object.__dict__` is the dictionary containing the class's namespace; :attr:"
|
|
"`~class.__bases__` is a tuple (possibly empty or a singleton) containing the "
|
|
"base classes, in the order of their occurrence in the base class list; :attr:"
|
|
"`__doc__` is the class's documentation string, or ``None`` if undefined."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:842
|
|
msgid ""
|
|
"A class instance is created by calling a class object (see above). A class "
|
|
"instance has a namespace implemented as a dictionary which is the first "
|
|
"place in which attribute references are searched. When an attribute is not "
|
|
"found there, and the instance's class has an attribute by that name, the "
|
|
"search continues with the class attributes. If a class attribute is found "
|
|
"that is a user-defined function object or an unbound user-defined method "
|
|
"object whose associated class is the class (call it :class:`C`) of the "
|
|
"instance for which the attribute reference was initiated or one of its "
|
|
"bases, it is transformed into a bound user-defined method object whose :attr:"
|
|
"`im_class` attribute is :class:`C` and whose :attr:`im_self` attribute is "
|
|
"the instance. Static method and class method objects are also transformed, "
|
|
"as if they had been retrieved from class :class:`C`; see above under "
|
|
"\"Classes\". See section :ref:`descriptors` for another way in which "
|
|
"attributes of a class retrieved via its instances may differ from the "
|
|
"objects actually stored in the class's :attr:`~object.__dict__`. If no class "
|
|
"attribute is found, and the object's class has a :meth:`__getattr__` method, "
|
|
"that is called to satisfy the lookup."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:861
|
|
msgid ""
|
|
"Attribute assignments and deletions update the instance's dictionary, never "
|
|
"a class's dictionary. If the class has a :meth:`__setattr__` or :meth:"
|
|
"`__delattr__` method, this is called instead of updating the instance "
|
|
"dictionary directly."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:871
|
|
msgid ""
|
|
"Class instances can pretend to be numbers, sequences, or mappings if they "
|
|
"have methods with certain special names. See section :ref:`specialnames`."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:878
|
|
msgid ""
|
|
"Special attributes: :attr:`~object.__dict__` is the attribute dictionary; :"
|
|
"attr:`~instance.__class__` is the instance's class."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:902
|
|
msgid "Files"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:895
|
|
msgid ""
|
|
"A file object represents an open file. File objects are created by the :"
|
|
"func:`open` built-in function, and also by :func:`os.popen`, :func:`os."
|
|
"fdopen`, and the :meth:`makefile` method of socket objects (and perhaps by "
|
|
"other functions or methods provided by extension modules). The objects "
|
|
"``sys.stdin``, ``sys.stdout`` and ``sys.stderr`` are initialized to file "
|
|
"objects corresponding to the interpreter's standard input, output and error "
|
|
"streams. See :ref:`bltin-file-objects` for complete documentation of file "
|
|
"objects."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1110
|
|
msgid "Internal types"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:909
|
|
msgid ""
|
|
"A few types used internally by the interpreter are exposed to the user. "
|
|
"Their definitions may change with future versions of the interpreter, but "
|
|
"they are mentioned here for completeness."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:977
|
|
msgid "Code objects"
|
|
msgstr "Objets Code"
|
|
|
|
#: ../Doc/reference/datamodel.rst:916
|
|
msgid ""
|
|
"Code objects represent *byte-compiled* executable Python code, or :term:"
|
|
"`bytecode`. The difference between a code object and a function object is "
|
|
"that the function object contains an explicit reference to the function's "
|
|
"globals (the module in which it was defined), while a code object contains "
|
|
"no context; also the default argument values are stored in the function "
|
|
"object, not in the code object (because they represent values calculated at "
|
|
"run-time). Unlike function objects, code objects are immutable and contain "
|
|
"no references (directly or indirectly) to mutable objects."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:941
|
|
msgid ""
|
|
"Special read-only attributes: :attr:`co_name` gives the function name; :attr:"
|
|
"`co_argcount` is the number of positional arguments (including arguments "
|
|
"with default values); :attr:`co_nlocals` is the number of local variables "
|
|
"used by the function (including arguments); :attr:`co_varnames` is a tuple "
|
|
"containing the names of the local variables (starting with the argument "
|
|
"names); :attr:`co_cellvars` is a tuple containing the names of local "
|
|
"variables that are referenced by nested functions; :attr:`co_freevars` is a "
|
|
"tuple containing the names of free variables; :attr:`co_code` is a string "
|
|
"representing the sequence of bytecode instructions; :attr:`co_consts` is a "
|
|
"tuple containing the literals used by the bytecode; :attr:`co_names` is a "
|
|
"tuple containing the names used by the bytecode; :attr:`co_filename` is the "
|
|
"filename from which the code was compiled; :attr:`co_firstlineno` is the "
|
|
"first line number of the function; :attr:`co_lnotab` is a string encoding "
|
|
"the mapping from bytecode offsets to line numbers (for details see the "
|
|
"source code of the interpreter); :attr:`co_stacksize` is the required stack "
|
|
"size (including local variables); :attr:`co_flags` is an integer encoding a "
|
|
"number of flags for the interpreter."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:960
|
|
msgid ""
|
|
"The following flag bits are defined for :attr:`co_flags`: bit ``0x04`` is "
|
|
"set if the function uses the ``*arguments`` syntax to accept an arbitrary "
|
|
"number of positional arguments; bit ``0x08`` is set if the function uses the "
|
|
"``**keywords`` syntax to accept arbitrary keyword arguments; bit ``0x20`` is "
|
|
"set if the function is a generator."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:966
|
|
msgid ""
|
|
"Future feature declarations (``from __future__ import division``) also use "
|
|
"bits in :attr:`co_flags` to indicate whether a code object was compiled with "
|
|
"a particular feature enabled: bit ``0x2000`` is set if the function was "
|
|
"compiled with future division enabled; bits ``0x10`` and ``0x1000`` were "
|
|
"used in earlier versions of Python."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:972
|
|
msgid "Other bits in :attr:`co_flags` are reserved for internal use."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:976
|
|
msgid ""
|
|
"If a code object represents a function, the first item in :attr:`co_consts` "
|
|
"is the documentation string of the function, or ``None`` if undefined."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1019
|
|
msgid "Frame objects"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:984
|
|
msgid ""
|
|
"Frame objects represent execution frames. They may occur in traceback "
|
|
"objects (see below)."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:996
|
|
msgid ""
|
|
"Special read-only attributes: :attr:`f_back` is to the previous stack frame "
|
|
"(towards the caller), or ``None`` if this is the bottom stack frame; :attr:"
|
|
"`f_code` is the code object being executed in this frame; :attr:`f_locals` "
|
|
"is the dictionary used to look up local variables; :attr:`f_globals` is used "
|
|
"for global variables; :attr:`f_builtins` is used for built-in (intrinsic) "
|
|
"names; :attr:`f_restricted` is a flag indicating whether the function is "
|
|
"executing in restricted execution mode; :attr:`f_lasti` gives the precise "
|
|
"instruction (this is an index into the bytecode string of the code object)."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1012
|
|
msgid ""
|
|
"Special writable attributes: :attr:`f_trace`, if not ``None``, is a function "
|
|
"called at the start of each source code line (this is used by the "
|
|
"debugger); :attr:`f_exc_type`, :attr:`f_exc_value`, :attr:`f_exc_traceback` "
|
|
"represent the last exception raised in the parent frame provided another "
|
|
"exception was ever raised in the current frame (in all other cases they are "
|
|
"``None``); :attr:`f_lineno` is the current line number of the frame --- "
|
|
"writing to this from within a trace function jumps to the given line (only "
|
|
"for the bottom-most frame). A debugger can implement a Jump command (aka "
|
|
"Set Next Statement) by writing to f_lineno."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1061
|
|
msgid "Traceback objects"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1034
|
|
msgid ""
|
|
"Traceback objects represent a stack trace of an exception. A traceback "
|
|
"object is created when an exception occurs. When the search for an "
|
|
"exception handler unwinds the execution stack, at each unwound level a "
|
|
"traceback object is inserted in front of the current traceback. When an "
|
|
"exception handler is entered, the stack trace is made available to the "
|
|
"program. (See section :ref:`try`.) It is accessible as ``sys."
|
|
"exc_traceback``, and also as the third item of the tuple returned by ``sys."
|
|
"exc_info()``. The latter is the preferred interface, since it works "
|
|
"correctly when the program is using multiple threads. When the program "
|
|
"contains no suitable handler, the stack trace is written (nicely formatted) "
|
|
"to the standard error stream; if the interpreter is interactive, it is also "
|
|
"made available to the user as ``sys.last_traceback``."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1054
|
|
msgid ""
|
|
"Special read-only attributes: :attr:`tb_next` is the next level in the stack "
|
|
"trace (towards the frame where the exception occurred), or ``None`` if there "
|
|
"is no next level; :attr:`tb_frame` points to the execution frame of the "
|
|
"current level; :attr:`tb_lineno` gives the line number where the exception "
|
|
"occurred; :attr:`tb_lasti` indicates the precise instruction. The line "
|
|
"number and last instruction in the traceback may differ from the line number "
|
|
"of its frame object if the exception occurred in a :keyword:`try` statement "
|
|
"with no matching except clause or with a finally clause."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1092
|
|
msgid "Slice objects"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1066
|
|
msgid ""
|
|
"Slice objects are used to represent slices when *extended slice syntax* is "
|
|
"used. This is a slice using two colons, or multiple slices or ellipses "
|
|
"separated by commas, e.g., ``a[i:j:step]``, ``a[i:j, k:l]``, or ``a[..., i:"
|
|
"j]``. They are also created by the built-in :func:`slice` function."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1076
|
|
msgid ""
|
|
"Special read-only attributes: :attr:`~slice.start` is the lower bound; :attr:"
|
|
"`~slice.stop` is the upper bound; :attr:`~slice.step` is the step value; "
|
|
"each is ``None`` if omitted. These attributes can have any type."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1080
|
|
msgid "Slice objects support one method:"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1085
|
|
msgid ""
|
|
"This method takes a single integer argument *length* and computes "
|
|
"information about the extended slice that the slice object would describe if "
|
|
"applied to a sequence of *length* items. It returns a tuple of three "
|
|
"integers; respectively these are the *start* and *stop* indices and the "
|
|
"*step* or stride length of the slice. Missing or out-of-bounds indices are "
|
|
"handled in a manner consistent with regular slices."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1102
|
|
msgid "Static method objects"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1095
|
|
msgid ""
|
|
"Static method objects provide a way of defeating the transformation of "
|
|
"function objects to method objects described above. A static method object "
|
|
"is a wrapper around any other object, usually a user-defined method object. "
|
|
"When a static method object is retrieved from a class or a class instance, "
|
|
"the object actually returned is the wrapped object, which is not subject to "
|
|
"any further transformation. Static method objects are not themselves "
|
|
"callable, although the objects they wrap usually are. Static method objects "
|
|
"are created by the built-in :func:`staticmethod` constructor."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1110
|
|
msgid "Class method objects"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1105
|
|
msgid ""
|
|
"A class method object, like a static method object, is a wrapper around "
|
|
"another object that alters the way in which that object is retrieved from "
|
|
"classes and class instances. The behaviour of class method objects upon such "
|
|
"retrieval is described above, under \"User-defined methods\". Class method "
|
|
"objects are created by the built-in :func:`classmethod` constructor."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1115
|
|
msgid "New-style and classic classes"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1117
|
|
msgid ""
|
|
"Classes and instances come in two flavors: old-style (or classic) and new-"
|
|
"style."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1119
|
|
msgid ""
|
|
"Up to Python 2.1 the concept of ``class`` was unrelated to the concept of "
|
|
"``type``, and old-style classes were the only flavor available. For an old-"
|
|
"style class, the statement ``x.__class__`` provides the class of *x*, but "
|
|
"``type(x)`` is always ``<type 'instance'>``. This reflects the fact that "
|
|
"all old-style instances, independent of their class, are implemented with a "
|
|
"single built-in type, called ``instance``."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1126
|
|
msgid ""
|
|
"New-style classes were introduced in Python 2.2 to unify the concepts of "
|
|
"``class`` and ``type``. A new-style class is simply a user-defined type, no "
|
|
"more, no less. If *x* is an instance of a new-style class, then ``type(x)`` "
|
|
"is typically the same as ``x.__class__`` (although this is not guaranteed -- "
|
|
"a new-style class instance is permitted to override the value returned for "
|
|
"``x.__class__``)."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1133
|
|
msgid ""
|
|
"The major motivation for introducing new-style classes is to provide a "
|
|
"unified object model with a full meta-model. It also has a number of "
|
|
"practical benefits, like the ability to subclass most built-in types, or the "
|
|
"introduction of \"descriptors\", which enable computed properties."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1138
|
|
msgid ""
|
|
"For compatibility reasons, classes are still old-style by default. New-"
|
|
"style classes are created by specifying another new-style class (i.e. a "
|
|
"type) as a parent class, or the \"top-level type\" :class:`object` if no "
|
|
"other parent is needed. The behaviour of new-style classes differs from "
|
|
"that of old-style classes in a number of important details in addition to "
|
|
"what :func:`type` returns. Some of these changes are fundamental to the new "
|
|
"object model, like the way special methods are invoked. Others are \"fixes"
|
|
"\" that could not be implemented before for compatibility concerns, like the "
|
|
"method resolution order in case of multiple inheritance."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1148
|
|
msgid ""
|
|
"While this manual aims to provide comprehensive coverage of Python's class "
|
|
"mechanics, it may still be lacking in some areas when it comes to its "
|
|
"coverage of new-style classes. Please see https://www.python.org/doc/"
|
|
"newstyle/ for sources of additional information."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1158
|
|
msgid ""
|
|
"Old-style classes are removed in Python 3, leaving only new-style classes."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1164
|
|
msgid "Special method names"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1170
|
|
msgid ""
|
|
"A class can implement certain operations that are invoked by special syntax "
|
|
"(such as arithmetic operations or subscripting and slicing) by defining "
|
|
"methods with special names. This is Python's approach to :dfn:`operator "
|
|
"overloading`, allowing classes to define their own behavior with respect to "
|
|
"language operators. For instance, if a class defines a method named :meth:"
|
|
"`__getitem__`, and ``x`` is an instance of this class, then ``x[i]`` is "
|
|
"roughly equivalent to ``x.__getitem__(i)`` for old-style classes and "
|
|
"``type(x).__getitem__(x, i)`` for new-style classes. Except where "
|
|
"mentioned, attempts to execute an operation raise an exception when no "
|
|
"appropriate method is defined (typically :exc:`AttributeError` or :exc:"
|
|
"`TypeError`)."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1181
|
|
msgid ""
|
|
"When implementing a class that emulates any built-in type, it is important "
|
|
"that the emulation only be implemented to the degree that it makes sense for "
|
|
"the object being modelled. For example, some sequences may work well with "
|
|
"retrieval of individual elements, but extracting a slice may not make "
|
|
"sense. (One example of this is the :class:`~xml.dom.NodeList` interface in "
|
|
"the W3C's Document Object Model.)"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1192
|
|
msgid "Basic customization"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1198
|
|
msgid ""
|
|
"Called to create a new instance of class *cls*. :meth:`__new__` is a static "
|
|
"method (special-cased so you need not declare it as such) that takes the "
|
|
"class of which an instance was requested as its first argument. The "
|
|
"remaining arguments are those passed to the object constructor expression "
|
|
"(the call to the class). The return value of :meth:`__new__` should be the "
|
|
"new object instance (usually an instance of *cls*)."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1205
|
|
msgid ""
|
|
"Typical implementations create a new instance of the class by invoking the "
|
|
"superclass's :meth:`__new__` method using ``super(currentclass, cls)."
|
|
"__new__(cls[, ...])`` with appropriate arguments and then modifying the "
|
|
"newly-created instance as necessary before returning it."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1210
|
|
msgid ""
|
|
"If :meth:`__new__` returns an instance of *cls*, then the new instance's :"
|
|
"meth:`__init__` method will be invoked like ``__init__(self[, ...])``, where "
|
|
"*self* is the new instance and the remaining arguments are the same as were "
|
|
"passed to :meth:`__new__`."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1215
|
|
msgid ""
|
|
"If :meth:`__new__` does not return an instance of *cls*, then the new "
|
|
"instance's :meth:`__init__` method will not be invoked."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1218
|
|
msgid ""
|
|
":meth:`__new__` is intended mainly to allow subclasses of immutable types "
|
|
"(like int, str, or tuple) to customize instance creation. It is also "
|
|
"commonly overridden in custom metaclasses in order to customize class "
|
|
"creation."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1227
|
|
msgid ""
|
|
"Called after the instance has been created (by :meth:`__new__`), but before "
|
|
"it is returned to the caller. The arguments are those passed to the class "
|
|
"constructor expression. If a base class has an :meth:`__init__` method, the "
|
|
"derived class's :meth:`__init__` method, if any, must explicitly call it to "
|
|
"ensure proper initialization of the base class part of the instance; for "
|
|
"example: ``BaseClass.__init__(self, [args...])``."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1234
|
|
msgid ""
|
|
"Because :meth:`__new__` and :meth:`__init__` work together in constructing "
|
|
"objects (:meth:`__new__` to create it, and :meth:`__init__` to customise "
|
|
"it), no non-``None`` value may be returned by :meth:`__init__`; doing so "
|
|
"will cause a :exc:`TypeError` to be raised at runtime."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1246
|
|
msgid ""
|
|
"Called when the instance is about to be destroyed. This is also called a "
|
|
"destructor. If a base class has a :meth:`__del__` method, the derived "
|
|
"class's :meth:`__del__` method, if any, must explicitly call it to ensure "
|
|
"proper deletion of the base class part of the instance. Note that it is "
|
|
"possible (though not recommended!) for the :meth:`__del__` method to "
|
|
"postpone destruction of the instance by creating a new reference to it. It "
|
|
"may then be called at a later time when this new reference is deleted. It "
|
|
"is not guaranteed that :meth:`__del__` methods are called for objects that "
|
|
"still exist when the interpreter exits."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1258
|
|
msgid ""
|
|
"``del x`` doesn't directly call ``x.__del__()`` --- the former decrements "
|
|
"the reference count for ``x`` by one, and the latter is only called when "
|
|
"``x``'s reference count reaches zero. Some common situations that may "
|
|
"prevent the reference count of an object from going to zero include: "
|
|
"circular references between objects (e.g., a doubly-linked list or a tree "
|
|
"data structure with parent and child pointers); a reference to the object on "
|
|
"the stack frame of a function that caught an exception (the traceback stored "
|
|
"in ``sys.exc_traceback`` keeps the stack frame alive); or a reference to the "
|
|
"object on the stack frame that raised an unhandled exception in interactive "
|
|
"mode (the traceback stored in ``sys.last_traceback`` keeps the stack frame "
|
|
"alive). The first situation can only be remedied by explicitly breaking the "
|
|
"cycles; the latter two situations can be resolved by storing ``None`` in "
|
|
"``sys.exc_traceback`` or ``sys.last_traceback``. Circular references which "
|
|
"are garbage are detected when the option cycle detector is enabled (it's on "
|
|
"by default), but can only be cleaned up if there are no Python-level :meth:"
|
|
"`__del__` methods involved. Refer to the documentation for the :mod:`gc` "
|
|
"module for more information about how :meth:`__del__` methods are handled by "
|
|
"the cycle detector, particularly the description of the ``garbage`` value."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1280
|
|
msgid ""
|
|
"Due to the precarious circumstances under which :meth:`__del__` methods are "
|
|
"invoked, exceptions that occur during their execution are ignored, and a "
|
|
"warning is printed to ``sys.stderr`` instead. Also, when :meth:`__del__` is "
|
|
"invoked in response to a module being deleted (e.g., when execution of the "
|
|
"program is done), other globals referenced by the :meth:`__del__` method may "
|
|
"already have been deleted or in the process of being torn down (e.g. the "
|
|
"import machinery shutting down). For this reason, :meth:`__del__` methods "
|
|
"should do the absolute minimum needed to maintain external invariants. "
|
|
"Starting with version 1.5, Python guarantees that globals whose name begins "
|
|
"with a single underscore are deleted from their module before other globals "
|
|
"are deleted; if no other references to such globals exist, this may help in "
|
|
"assuring that imported modules are still available at the time when the :"
|
|
"meth:`__del__` method is called."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1295
|
|
msgid "See also the :option:`-R` command-line option."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1302
|
|
msgid ""
|
|
"Called by the :func:`repr` built-in function and by string conversions "
|
|
"(reverse quotes) to compute the \"official\" string representation of an "
|
|
"object. If at all possible, this should look like a valid Python expression "
|
|
"that could be used to recreate an object with the same value (given an "
|
|
"appropriate environment). If this is not possible, a string of the form "
|
|
"``<...some useful description...>`` should be returned. The return value "
|
|
"must be a string object. If a class defines :meth:`__repr__` but not :meth:"
|
|
"`__str__`, then :meth:`__repr__` is also used when an \"informal\" string "
|
|
"representation of instances of that class is required."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1318
|
|
msgid ""
|
|
"This is typically used for debugging, so it is important that the "
|
|
"representation is information-rich and unambiguous."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1328
|
|
msgid ""
|
|
"Called by the :func:`str` built-in function and by the :keyword:`print` "
|
|
"statement to compute the \"informal\" string representation of an object. "
|
|
"This differs from :meth:`__repr__` in that it does not have to be a valid "
|
|
"Python expression: a more convenient or concise representation may be used "
|
|
"instead. The return value must be a string object."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1347
|
|
msgid ""
|
|
"These are the so-called \"rich comparison\" methods, and are called for "
|
|
"comparison operators in preference to :meth:`__cmp__` below. The "
|
|
"correspondence between operator symbols and method names is as follows: "
|
|
"``x<y`` calls ``x.__lt__(y)``, ``x<=y`` calls ``x.__le__(y)``, ``x==y`` "
|
|
"calls ``x.__eq__(y)``, ``x!=y`` and ``x<>y`` call ``x.__ne__(y)``, ``x>y`` "
|
|
"calls ``x.__gt__(y)``, and ``x>=y`` calls ``x.__ge__(y)``."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1354
|
|
msgid ""
|
|
"A rich comparison method may return the singleton ``NotImplemented`` if it "
|
|
"does not implement the operation for a given pair of arguments. By "
|
|
"convention, ``False`` and ``True`` are returned for a successful comparison. "
|
|
"However, these methods can return any value, so if the comparison operator "
|
|
"is used in a Boolean context (e.g., in the condition of an ``if`` "
|
|
"statement), Python will call :func:`bool` on the value to determine if the "
|
|
"result is true or false."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1361
|
|
msgid ""
|
|
"There are no implied relationships among the comparison operators. The truth "
|
|
"of ``x==y`` does not imply that ``x!=y`` is false. Accordingly, when "
|
|
"defining :meth:`__eq__`, one should also define :meth:`__ne__` so that the "
|
|
"operators will behave as expected. See the paragraph on :meth:`__hash__` "
|
|
"for some important notes on creating :term:`hashable` objects which support "
|
|
"custom comparison operations and are usable as dictionary keys."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1368
|
|
msgid ""
|
|
"There are no swapped-argument versions of these methods (to be used when the "
|
|
"left argument does not support the operation but the right argument does); "
|
|
"rather, :meth:`__lt__` and :meth:`__gt__` are each other's reflection, :meth:"
|
|
"`__le__` and :meth:`__ge__` are each other's reflection, and :meth:`__eq__` "
|
|
"and :meth:`__ne__` are their own reflection."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1374
|
|
msgid "Arguments to rich comparison methods are never coerced."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1376
|
|
msgid ""
|
|
"To automatically generate ordering operations from a single root operation, "
|
|
"see :func:`functools.total_ordering`."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1385
|
|
msgid ""
|
|
"Called by comparison operations if rich comparison (see above) is not "
|
|
"defined. Should return a negative integer if ``self < other``, zero if "
|
|
"``self == other``, a positive integer if ``self > other``. If no :meth:"
|
|
"`__cmp__`, :meth:`__eq__` or :meth:`__ne__` operation is defined, class "
|
|
"instances are compared by object identity (\"address\"). See also the "
|
|
"description of :meth:`__hash__` for some important notes on creating :term:"
|
|
"`hashable` objects which support custom comparison operations and are usable "
|
|
"as dictionary keys. (Note: the restriction that exceptions are not "
|
|
"propagated by :meth:`__cmp__` has been removed since Python 1.5.)"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1398
|
|
msgid "No longer supported."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1408
|
|
msgid ""
|
|
"Called by built-in function :func:`hash` and for operations on members of "
|
|
"hashed collections including :class:`set`, :class:`frozenset`, and :class:"
|
|
"`dict`. :meth:`__hash__` should return an integer. The only required "
|
|
"property is that objects which compare equal have the same hash value; it is "
|
|
"advised to somehow mix together (e.g. using exclusive or) the hash values "
|
|
"for the components of the object that also play a part in comparison of "
|
|
"objects."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1415
|
|
msgid ""
|
|
"If a class does not define a :meth:`__cmp__` or :meth:`__eq__` method it "
|
|
"should not define a :meth:`__hash__` operation either; if it defines :meth:"
|
|
"`__cmp__` or :meth:`__eq__` but not :meth:`__hash__`, its instances will not "
|
|
"be usable in hashed collections. If a class defines mutable objects and "
|
|
"implements a :meth:`__cmp__` or :meth:`__eq__` method, it should not "
|
|
"implement :meth:`__hash__`, since hashable collection implementations "
|
|
"require that an object's hash value is immutable (if the object's hash value "
|
|
"changes, it will be in the wrong hash bucket)."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1424
|
|
msgid ""
|
|
"User-defined classes have :meth:`__cmp__` and :meth:`__hash__` methods by "
|
|
"default; with them, all objects compare unequal (except with themselves) and "
|
|
"``x.__hash__()`` returns a result derived from ``id(x)``."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1428
|
|
msgid ""
|
|
"Classes which inherit a :meth:`__hash__` method from a parent class but "
|
|
"change the meaning of :meth:`__cmp__` or :meth:`__eq__` such that the hash "
|
|
"value returned is no longer appropriate (e.g. by switching to a value-based "
|
|
"concept of equality instead of the default identity based equality) can "
|
|
"explicitly flag themselves as being unhashable by setting ``__hash__ = "
|
|
"None`` in the class definition. Doing so means that not only will instances "
|
|
"of the class raise an appropriate :exc:`TypeError` when a program attempts "
|
|
"to retrieve their hash value, but they will also be correctly identified as "
|
|
"unhashable when checking ``isinstance(obj, collections.Hashable)`` (unlike "
|
|
"classes which define their own :meth:`__hash__` to explicitly raise :exc:"
|
|
"`TypeError`)."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1440
|
|
msgid ""
|
|
":meth:`__hash__` may now also return a long integer object; the 32-bit "
|
|
"integer is then derived from the hash of that object."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1444
|
|
msgid ""
|
|
":attr:`__hash__` may now be set to :const:`None` to explicitly flag "
|
|
"instances of a class as unhashable."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1453
|
|
msgid ""
|
|
"Called to implement truth value testing and the built-in operation "
|
|
"``bool()``; should return ``False`` or ``True``, or their integer "
|
|
"equivalents ``0`` or ``1``. When this method is not defined, :meth:"
|
|
"`__len__` is called, if it is defined, and the object is considered true if "
|
|
"its result is nonzero. If a class defines neither :meth:`__len__` nor :meth:"
|
|
"`__nonzero__`, all its instances are considered true."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1465
|
|
msgid ""
|
|
"Called to implement :func:`unicode` built-in; should return a Unicode "
|
|
"object. When this method is not defined, string conversion is attempted, and "
|
|
"the result of string conversion is converted to Unicode using the system "
|
|
"default encoding."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1473
|
|
msgid "Customizing attribute access"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1475
|
|
msgid ""
|
|
"The following methods can be defined to customize the meaning of attribute "
|
|
"access (use of, assignment to, or deletion of ``x.name``) for class "
|
|
"instances."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1481
|
|
msgid ""
|
|
"Called when an attribute lookup has not found the attribute in the usual "
|
|
"places (i.e. it is not an instance attribute nor is it found in the class "
|
|
"tree for ``self``). ``name`` is the attribute name. This method should "
|
|
"return the (computed) attribute value or raise an :exc:`AttributeError` "
|
|
"exception."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1488
|
|
msgid ""
|
|
"Note that if the attribute is found through the normal mechanism, :meth:"
|
|
"`__getattr__` is not called. (This is an intentional asymmetry between :"
|
|
"meth:`__getattr__` and :meth:`__setattr__`.) This is done both for "
|
|
"efficiency reasons and because otherwise :meth:`__getattr__` would have no "
|
|
"way to access other attributes of the instance. Note that at least for "
|
|
"instance variables, you can fake total control by not inserting any values "
|
|
"in the instance attribute dictionary (but instead inserting them in another "
|
|
"object). See the :meth:`__getattribute__` method below for a way to "
|
|
"actually get total control in new-style classes."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1501
|
|
msgid ""
|
|
"Called when an attribute assignment is attempted. This is called instead of "
|
|
"the normal mechanism (i.e. store the value in the instance dictionary). "
|
|
"*name* is the attribute name, *value* is the value to be assigned to it."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1507
|
|
msgid ""
|
|
"If :meth:`__setattr__` wants to assign to an instance attribute, it should "
|
|
"not simply execute ``self.name = value`` --- this would cause a recursive "
|
|
"call to itself. Instead, it should insert the value in the dictionary of "
|
|
"instance attributes, e.g., ``self.__dict__[name] = value``. For new-style "
|
|
"classes, rather than accessing the instance dictionary, it should call the "
|
|
"base class method with the same name, for example, ``object."
|
|
"__setattr__(self, name, value)``."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1518
|
|
msgid ""
|
|
"Like :meth:`__setattr__` but for attribute deletion instead of assignment. "
|
|
"This should only be implemented if ``del obj.name`` is meaningful for the "
|
|
"object."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1525
|
|
msgid "More attribute access for new-style classes"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1527
|
|
msgid "The following methods only apply to new-style classes."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1532
|
|
msgid ""
|
|
"Called unconditionally to implement attribute accesses for instances of the "
|
|
"class. If the class also defines :meth:`__getattr__`, the latter will not be "
|
|
"called unless :meth:`__getattribute__` either calls it explicitly or raises "
|
|
"an :exc:`AttributeError`. This method should return the (computed) attribute "
|
|
"value or raise an :exc:`AttributeError` exception. In order to avoid "
|
|
"infinite recursion in this method, its implementation should always call the "
|
|
"base class method with the same name to access any attributes it needs, for "
|
|
"example, ``object.__getattribute__(self, name)``."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1543
|
|
msgid ""
|
|
"This method may still be bypassed when looking up special methods as the "
|
|
"result of implicit invocation via language syntax or built-in functions. "
|
|
"See :ref:`new-style-special-lookup`."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1551
|
|
msgid "Implementing Descriptors"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1553
|
|
msgid ""
|
|
"The following methods only apply when an instance of the class containing "
|
|
"the method (a so-called *descriptor* class) appears in an *owner* class (the "
|
|
"descriptor must be in either the owner's class dictionary or in the class "
|
|
"dictionary for one of its parents). In the examples below, \"the attribute"
|
|
"\" refers to the attribute whose name is the key of the property in the "
|
|
"owner class' :attr:`~object.__dict__`."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1563
|
|
msgid ""
|
|
"Called to get the attribute of the owner class (class attribute access) or "
|
|
"of an instance of that class (instance attribute access). *owner* is always "
|
|
"the owner class, while *instance* is the instance that the attribute was "
|
|
"accessed through, or ``None`` when the attribute is accessed through the "
|
|
"*owner*. This method should return the (computed) attribute value or raise "
|
|
"an :exc:`AttributeError` exception."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1573
|
|
msgid ""
|
|
"Called to set the attribute on an instance *instance* of the owner class to "
|
|
"a new value, *value*."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1579
|
|
msgid ""
|
|
"Called to delete the attribute on an instance *instance* of the owner class."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1585
|
|
msgid "Invoking Descriptors"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1587
|
|
msgid ""
|
|
"In general, a descriptor is an object attribute with \"binding behavior\", "
|
|
"one whose attribute access has been overridden by methods in the descriptor "
|
|
"protocol: :meth:`__get__`, :meth:`__set__`, and :meth:`__delete__`. If any "
|
|
"of those methods are defined for an object, it is said to be a descriptor."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1592
|
|
msgid ""
|
|
"The default behavior for attribute access is to get, set, or delete the "
|
|
"attribute from an object's dictionary. For instance, ``a.x`` has a lookup "
|
|
"chain starting with ``a.__dict__['x']``, then ``type(a).__dict__['x']``, and "
|
|
"continuing through the base classes of ``type(a)`` excluding metaclasses."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1597
|
|
msgid ""
|
|
"However, if the looked-up value is an object defining one of the descriptor "
|
|
"methods, then Python may override the default behavior and invoke the "
|
|
"descriptor method instead. Where this occurs in the precedence chain "
|
|
"depends on which descriptor methods were defined and how they were called. "
|
|
"Note that descriptors are only invoked for new style objects or classes "
|
|
"(ones that subclass :class:`object()` or :class:`type()`)."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1604
|
|
msgid ""
|
|
"The starting point for descriptor invocation is a binding, ``a.x``. How the "
|
|
"arguments are assembled depends on ``a``:"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1609
|
|
msgid "Direct Call"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1608
|
|
msgid ""
|
|
"The simplest and least common call is when user code directly invokes a "
|
|
"descriptor method: ``x.__get__(a)``."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1613
|
|
msgid "Instance Binding"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1612
|
|
msgid ""
|
|
"If binding to a new-style object instance, ``a.x`` is transformed into the "
|
|
"call: ``type(a).__dict__['x'].__get__(a, type(a))``."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1617
|
|
msgid "Class Binding"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1616
|
|
msgid ""
|
|
"If binding to a new-style class, ``A.x`` is transformed into the call: ``A."
|
|
"__dict__['x'].__get__(None, A)``."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1623
|
|
msgid "Super Binding"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1620
|
|
msgid ""
|
|
"If ``a`` is an instance of :class:`super`, then the binding ``super(B, obj)."
|
|
"m()`` searches ``obj.__class__.__mro__`` for the base class ``A`` "
|
|
"immediately preceding ``B`` and then invokes the descriptor with the call: "
|
|
"``A.__dict__['m'].__get__(obj, obj.__class__)``."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1625
|
|
msgid ""
|
|
"For instance bindings, the precedence of descriptor invocation depends on "
|
|
"the which descriptor methods are defined. A descriptor can define any "
|
|
"combination of :meth:`__get__`, :meth:`__set__` and :meth:`__delete__`. If "
|
|
"it does not define :meth:`__get__`, then accessing the attribute will return "
|
|
"the descriptor object itself unless there is a value in the object's "
|
|
"instance dictionary. If the descriptor defines :meth:`__set__` and/or :meth:"
|
|
"`__delete__`, it is a data descriptor; if it defines neither, it is a non-"
|
|
"data descriptor. Normally, data descriptors define both :meth:`__get__` "
|
|
"and :meth:`__set__`, while non-data descriptors have just the :meth:"
|
|
"`__get__` method. Data descriptors with :meth:`__set__` and :meth:`__get__` "
|
|
"defined always override a redefinition in an instance dictionary. In "
|
|
"contrast, non-data descriptors can be overridden by instances."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1638
|
|
msgid ""
|
|
"Python methods (including :func:`staticmethod` and :func:`classmethod`) are "
|
|
"implemented as non-data descriptors. Accordingly, instances can redefine "
|
|
"and override methods. This allows individual instances to acquire behaviors "
|
|
"that differ from other instances of the same class."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1643
|
|
msgid ""
|
|
"The :func:`property` function is implemented as a data descriptor. "
|
|
"Accordingly, instances cannot override the behavior of a property."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1650
|
|
msgid "__slots__"
|
|
msgstr "__slots__"
|
|
|
|
#: ../Doc/reference/datamodel.rst:1652
|
|
msgid ""
|
|
"By default, instances of both old and new-style classes have a dictionary "
|
|
"for attribute storage. This wastes space for objects having very few "
|
|
"instance variables. The space consumption can become acute when creating "
|
|
"large numbers of instances."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1657
|
|
msgid ""
|
|
"The default can be overridden by defining *__slots__* in a new-style class "
|
|
"definition. The *__slots__* declaration takes a sequence of instance "
|
|
"variables and reserves just enough space in each instance to hold a value "
|
|
"for each variable. Space is saved because *__dict__* is not created for "
|
|
"each instance."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1665
|
|
msgid ""
|
|
"This class variable can be assigned a string, iterable, or sequence of "
|
|
"strings with variable names used by instances. If defined in a new-style "
|
|
"class, *__slots__* reserves space for the declared variables and prevents "
|
|
"the automatic creation of *__dict__* and *__weakref__* for each instance."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1672
|
|
msgid "Notes on using *__slots__*"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1674
|
|
msgid ""
|
|
"When inheriting from a class without *__slots__*, the *__dict__* attribute "
|
|
"of that class will always be accessible, so a *__slots__* definition in the "
|
|
"subclass is meaningless."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1678
|
|
msgid ""
|
|
"Without a *__dict__* variable, instances cannot be assigned new variables "
|
|
"not listed in the *__slots__* definition. Attempts to assign to an unlisted "
|
|
"variable name raises :exc:`AttributeError`. If dynamic assignment of new "
|
|
"variables is desired, then add ``'__dict__'`` to the sequence of strings in "
|
|
"the *__slots__* declaration."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1684
|
|
msgid ""
|
|
"Previously, adding ``'__dict__'`` to the *__slots__* declaration would not "
|
|
"enable the assignment of new attributes not specifically listed in the "
|
|
"sequence of instance variable names."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1689
|
|
msgid ""
|
|
"Without a *__weakref__* variable for each instance, classes defining "
|
|
"*__slots__* do not support weak references to its instances. If weak "
|
|
"reference support is needed, then add ``'__weakref__'`` to the sequence of "
|
|
"strings in the *__slots__* declaration."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1694
|
|
msgid ""
|
|
"Previously, adding ``'__weakref__'`` to the *__slots__* declaration would "
|
|
"not enable support for weak references."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1698
|
|
msgid ""
|
|
"*__slots__* are implemented at the class level by creating descriptors (:ref:"
|
|
"`descriptors`) for each variable name. As a result, class attributes cannot "
|
|
"be used to set default values for instance variables defined by *__slots__*; "
|
|
"otherwise, the class attribute would overwrite the descriptor assignment."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1704
|
|
msgid ""
|
|
"The action of a *__slots__* declaration is limited to the class where it is "
|
|
"defined. As a result, subclasses will have a *__dict__* unless they also "
|
|
"define *__slots__* (which must only contain names of any *additional* slots)."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1708
|
|
msgid ""
|
|
"If a class defines a slot also defined in a base class, the instance "
|
|
"variable defined by the base class slot is inaccessible (except by "
|
|
"retrieving its descriptor directly from the base class). This renders the "
|
|
"meaning of the program undefined. In the future, a check may be added to "
|
|
"prevent this."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1713
|
|
msgid ""
|
|
"Nonempty *__slots__* does not work for classes derived from \"variable-length"
|
|
"\" built-in types such as :class:`long`, :class:`str` and :class:`tuple`."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1716
|
|
msgid ""
|
|
"Any non-string iterable may be assigned to *__slots__*. Mappings may also be "
|
|
"used; however, in the future, special meaning may be assigned to the values "
|
|
"corresponding to each key."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1720
|
|
msgid ""
|
|
"*__class__* assignment works only if both classes have the same *__slots__*."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1722
|
|
msgid ""
|
|
"Previously, *__class__* assignment raised an error if either new or old "
|
|
"class had *__slots__*."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1730
|
|
msgid "Customizing class creation"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1732
|
|
msgid ""
|
|
"By default, new-style classes are constructed using :func:`type`. A class "
|
|
"definition is read into a separate namespace and the value of class name is "
|
|
"bound to the result of ``type(name, bases, dict)``."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1736
|
|
msgid ""
|
|
"When the class definition is read, if *__metaclass__* is defined then the "
|
|
"callable assigned to it will be called instead of :func:`type`. This allows "
|
|
"classes or functions to be written which monitor or alter the class creation "
|
|
"process:"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1741
|
|
msgid "Modifying the class dictionary prior to the class being created."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1743
|
|
msgid ""
|
|
"Returning an instance of another class -- essentially performing the role of "
|
|
"a factory function."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1746
|
|
msgid ""
|
|
"These steps will have to be performed in the metaclass's :meth:`__new__` "
|
|
"method -- :meth:`type.__new__` can then be called from this method to create "
|
|
"a class with different properties. This example adds a new element to the "
|
|
"class dictionary before creating the class::"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1756
|
|
msgid ""
|
|
"You can of course also override other class methods (or add new methods); "
|
|
"for example defining a custom :meth:`__call__` method in the metaclass "
|
|
"allows custom behavior when the class is called, e.g. not always creating a "
|
|
"new instance."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1763
|
|
msgid ""
|
|
"This variable can be any callable accepting arguments for ``name``, "
|
|
"``bases``, and ``dict``. Upon class creation, the callable is used instead "
|
|
"of the built-in :func:`type`."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1769
|
|
msgid ""
|
|
"The appropriate metaclass is determined by the following precedence rules:"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1771
|
|
msgid "If ``dict['__metaclass__']`` exists, it is used."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1773
|
|
msgid ""
|
|
"Otherwise, if there is at least one base class, its metaclass is used (this "
|
|
"looks for a *__class__* attribute first and if not found, uses its type)."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1776
|
|
msgid "Otherwise, if a global variable named __metaclass__ exists, it is used."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1778
|
|
msgid "Otherwise, the old-style, classic metaclass (types.ClassType) is used."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1780
|
|
msgid ""
|
|
"The potential uses for metaclasses are boundless. Some ideas that have been "
|
|
"explored including logging, interface checking, automatic delegation, "
|
|
"automatic property creation, proxies, frameworks, and automatic resource "
|
|
"locking/synchronization."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1787
|
|
msgid "Customizing instance and subclass checks"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1791
|
|
msgid ""
|
|
"The following methods are used to override the default behavior of the :func:"
|
|
"`isinstance` and :func:`issubclass` built-in functions."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1794
|
|
msgid ""
|
|
"In particular, the metaclass :class:`abc.ABCMeta` implements these methods "
|
|
"in order to allow the addition of Abstract Base Classes (ABCs) as \"virtual "
|
|
"base classes\" to any class or type (including built-in types), including "
|
|
"other ABCs."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1801
|
|
msgid ""
|
|
"Return true if *instance* should be considered a (direct or indirect) "
|
|
"instance of *class*. If defined, called to implement ``isinstance(instance, "
|
|
"class)``."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1808
|
|
msgid ""
|
|
"Return true if *subclass* should be considered a (direct or indirect) "
|
|
"subclass of *class*. If defined, called to implement ``issubclass(subclass, "
|
|
"class)``."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1813
|
|
msgid ""
|
|
"Note that these methods are looked up on the type (metaclass) of a class. "
|
|
"They cannot be defined as class methods in the actual class. This is "
|
|
"consistent with the lookup of special methods that are called on instances, "
|
|
"only in this case the instance is itself a class."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1824
|
|
msgid ":pep:`3119` - Introducing Abstract Base Classes"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1821
|
|
msgid ""
|
|
"Includes the specification for customizing :func:`isinstance` and :func:"
|
|
"`issubclass` behavior through :meth:`~class.__instancecheck__` and :meth:"
|
|
"`~class.__subclasscheck__`, with motivation for this functionality in the "
|
|
"context of adding Abstract Base Classes (see the :mod:`abc` module) to the "
|
|
"language."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1831
|
|
msgid "Emulating callable objects"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1838
|
|
msgid ""
|
|
"Called when the instance is \"called\" as a function; if this method is "
|
|
"defined, ``x(arg1, arg2, ...)`` is a shorthand for ``x.__call__(arg1, "
|
|
"arg2, ...)``."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1845
|
|
msgid "Emulating container types"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1847
|
|
msgid ""
|
|
"The following methods can be defined to implement container objects. "
|
|
"Containers usually are sequences (such as lists or tuples) or mappings (like "
|
|
"dictionaries), but can represent other containers as well. The first set of "
|
|
"methods is used either to emulate a sequence or to emulate a mapping; the "
|
|
"difference is that for a sequence, the allowable keys should be the integers "
|
|
"*k* for which ``0 <= k < N`` where *N* is the length of the sequence, or "
|
|
"slice objects, which define a range of items. (For backwards compatibility, "
|
|
"the method :meth:`__getslice__` (see below) can also be defined to handle "
|
|
"simple, but not extended slices.) It is also recommended that mappings "
|
|
"provide the methods :meth:`keys`, :meth:`values`, :meth:`items`, :meth:"
|
|
"`has_key`, :meth:`get`, :meth:`clear`, :meth:`setdefault`, :meth:"
|
|
"`iterkeys`, :meth:`itervalues`, :meth:`iteritems`, :meth:`pop`, :meth:"
|
|
"`popitem`, :meth:`!copy`, and :meth:`update` behaving similar to those for "
|
|
"Python's standard dictionary objects. The :mod:`UserDict` module provides "
|
|
"a :class:`DictMixin` class to help create those methods from a base set of :"
|
|
"meth:`__getitem__`, :meth:`__setitem__`, :meth:`__delitem__`, and :meth:"
|
|
"`keys`. Mutable sequences should provide methods :meth:`append`, :meth:"
|
|
"`count`, :meth:`index`, :meth:`extend`, :meth:`insert`, :meth:`pop`, :meth:"
|
|
"`remove`, :meth:`reverse` and :meth:`sort`, like Python standard list "
|
|
"objects. Finally, sequence types should implement addition (meaning "
|
|
"concatenation) and multiplication (meaning repetition) by defining the "
|
|
"methods :meth:`__add__`, :meth:`__radd__`, :meth:`__iadd__`, :meth:"
|
|
"`__mul__`, :meth:`__rmul__` and :meth:`__imul__` described below; they "
|
|
"should not define :meth:`__coerce__` or other numerical operators. It is "
|
|
"recommended that both mappings and sequences implement the :meth:"
|
|
"`__contains__` method to allow efficient use of the ``in`` operator; for "
|
|
"mappings, ``in`` should be equivalent of :meth:`has_key`; for sequences, it "
|
|
"should search through the values. It is further recommended that both "
|
|
"mappings and sequences implement the :meth:`__iter__` method to allow "
|
|
"efficient iteration through the container; for mappings, :meth:`__iter__` "
|
|
"should be the same as :meth:`iterkeys`; for sequences, it should iterate "
|
|
"through the values."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1885
|
|
msgid ""
|
|
"Called to implement the built-in function :func:`len`. Should return the "
|
|
"length of the object, an integer ``>=`` 0. Also, an object that doesn't "
|
|
"define a :meth:`__nonzero__` method and whose :meth:`__len__` method returns "
|
|
"zero is considered to be false in a Boolean context."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1895
|
|
msgid ""
|
|
"Called to implement evaluation of ``self[key]``. For sequence types, the "
|
|
"accepted keys should be integers and slice objects. Note that the special "
|
|
"interpretation of negative indexes (if the class wishes to emulate a "
|
|
"sequence type) is up to the :meth:`__getitem__` method. If *key* is of an "
|
|
"inappropriate type, :exc:`TypeError` may be raised; if of a value outside "
|
|
"the set of indexes for the sequence (after any special interpretation of "
|
|
"negative values), :exc:`IndexError` should be raised. For mapping types, if "
|
|
"*key* is missing (not in the container), :exc:`KeyError` should be raised."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1906
|
|
msgid ""
|
|
":keyword:`for` loops expect that an :exc:`IndexError` will be raised for "
|
|
"illegal indexes to allow proper detection of the end of the sequence."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1912
|
|
msgid ""
|
|
"Called by :class:`dict`\\ .\\ :meth:`__getitem__` to implement ``self[key]`` "
|
|
"for dict subclasses when key is not in the dictionary."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1918
|
|
msgid ""
|
|
"Called to implement assignment to ``self[key]``. Same note as for :meth:"
|
|
"`__getitem__`. This should only be implemented for mappings if the objects "
|
|
"support changes to the values for keys, or if new keys can be added, or for "
|
|
"sequences if elements can be replaced. The same exceptions should be raised "
|
|
"for improper *key* values as for the :meth:`__getitem__` method."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1927
|
|
msgid ""
|
|
"Called to implement deletion of ``self[key]``. Same note as for :meth:"
|
|
"`__getitem__`. This should only be implemented for mappings if the objects "
|
|
"support removal of keys, or for sequences if elements can be removed from "
|
|
"the sequence. The same exceptions should be raised for improper *key* "
|
|
"values as for the :meth:`__getitem__` method."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1936
|
|
msgid ""
|
|
"This method is called when an iterator is required for a container. This "
|
|
"method should return a new iterator object that can iterate over all the "
|
|
"objects in the container. For mappings, it should iterate over the keys of "
|
|
"the container, and should also be made available as the method :meth:"
|
|
"`iterkeys`."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1941
|
|
msgid ""
|
|
"Iterator objects also need to implement this method; they are required to "
|
|
"return themselves. For more information on iterator objects, see :ref:"
|
|
"`typeiter`."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1947
|
|
msgid ""
|
|
"Called (if present) by the :func:`reversed` built-in to implement reverse "
|
|
"iteration. It should return a new iterator object that iterates over all "
|
|
"the objects in the container in reverse order."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1951
|
|
msgid ""
|
|
"If the :meth:`__reversed__` method is not provided, the :func:`reversed` "
|
|
"built-in will fall back to using the sequence protocol (:meth:`__len__` and :"
|
|
"meth:`__getitem__`). Objects that support the sequence protocol should only "
|
|
"provide :meth:`__reversed__` if they can provide an implementation that is "
|
|
"more efficient than the one provided by :func:`reversed`."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1960
|
|
msgid ""
|
|
"The membership test operators (:keyword:`in` and :keyword:`not in`) are "
|
|
"normally implemented as an iteration through a sequence. However, container "
|
|
"objects can supply the following special method with a more efficient "
|
|
"implementation, which also does not require the object be a sequence."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1967
|
|
msgid ""
|
|
"Called to implement membership test operators. Should return true if *item* "
|
|
"is in *self*, false otherwise. For mapping objects, this should consider "
|
|
"the keys of the mapping rather than the values or the key-item pairs."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1971
|
|
msgid ""
|
|
"For objects that don't define :meth:`__contains__`, the membership test "
|
|
"first tries iteration via :meth:`__iter__`, then the old sequence iteration "
|
|
"protocol via :meth:`__getitem__`, see :ref:`this section in the language "
|
|
"reference <membership-test-details>`."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1980
|
|
msgid "Additional methods for emulation of sequence types"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1982
|
|
msgid ""
|
|
"The following optional methods can be defined to further emulate sequence "
|
|
"objects. Immutable sequences methods should at most only define :meth:"
|
|
"`__getslice__`; mutable sequences might define all three methods."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1989
|
|
msgid ""
|
|
"Support slice objects as parameters to the :meth:`__getitem__` method. "
|
|
"(However, built-in types in CPython currently still implement :meth:"
|
|
"`__getslice__`. Therefore, you have to override it in derived classes when "
|
|
"implementing slicing.)"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:1995
|
|
msgid ""
|
|
"Called to implement evaluation of ``self[i:j]``. The returned object should "
|
|
"be of the same type as *self*. Note that missing *i* or *j* in the slice "
|
|
"expression are replaced by zero or :attr:`sys.maxsize`, respectively. If "
|
|
"negative indexes are used in the slice, the length of the sequence is added "
|
|
"to that index. If the instance does not implement the :meth:`__len__` "
|
|
"method, an :exc:`AttributeError` is raised. No guarantee is made that "
|
|
"indexes adjusted this way are not still negative. Indexes which are greater "
|
|
"than the length of the sequence are not modified. If no :meth:`__getslice__` "
|
|
"is found, a slice object is created instead, and passed to :meth:"
|
|
"`__getitem__` instead."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:2008
|
|
msgid ""
|
|
"Called to implement assignment to ``self[i:j]``. Same notes for *i* and *j* "
|
|
"as for :meth:`__getslice__`."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:2011
|
|
msgid ""
|
|
"This method is deprecated. If no :meth:`__setslice__` is found, or for "
|
|
"extended slicing of the form ``self[i:j:k]``, a slice object is created, and "
|
|
"passed to :meth:`__setitem__`, instead of :meth:`__setslice__` being called."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:2018
|
|
msgid ""
|
|
"Called to implement deletion of ``self[i:j]``. Same notes for *i* and *j* as "
|
|
"for :meth:`__getslice__`. This method is deprecated. If no :meth:"
|
|
"`__delslice__` is found, or for extended slicing of the form ``self[i:j:"
|
|
"k]``, a slice object is created, and passed to :meth:`__delitem__`, instead "
|
|
"of :meth:`__delslice__` being called."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:2024
|
|
msgid ""
|
|
"Notice that these methods are only invoked when a single slice with a single "
|
|
"colon is used, and the slice method is available. For slice operations "
|
|
"involving extended slice notation, or in absence of the slice methods, :meth:"
|
|
"`__getitem__`, :meth:`__setitem__` or :meth:`__delitem__` is called with a "
|
|
"slice object as argument."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:2030
|
|
msgid ""
|
|
"The following example demonstrate how to make your program or module "
|
|
"compatible with earlier versions of Python (assuming that methods :meth:"
|
|
"`__getitem__`, :meth:`__setitem__` and :meth:`__delitem__` support slice "
|
|
"objects as arguments)::"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:2055
|
|
msgid ""
|
|
"Note the calls to :func:`max`; these are necessary because of the handling "
|
|
"of negative indices before the :meth:`__\\*slice__` methods are called. "
|
|
"When negative indexes are used, the :meth:`__\\*item__` methods receive them "
|
|
"as provided, but the :meth:`__\\*slice__` methods get a \"cooked\" form of "
|
|
"the index values. For each negative index value, the length of the sequence "
|
|
"is added to the index before calling the method (which may still result in a "
|
|
"negative index); this is the customary handling of negative indexes by the "
|
|
"built-in sequence types, and the :meth:`__\\*item__` methods are expected to "
|
|
"do this as well. However, since they should already be doing that, negative "
|
|
"indexes cannot be passed in; they must be constrained to the bounds of the "
|
|
"sequence before being passed to the :meth:`__\\*item__` methods. Calling "
|
|
"``max(0, i)`` conveniently returns the proper value."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:2072
|
|
msgid "Emulating numeric types"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:2074
|
|
msgid ""
|
|
"The following methods can be defined to emulate numeric objects. Methods "
|
|
"corresponding to operations that are not supported by the particular kind of "
|
|
"number implemented (e.g., bitwise operations for non-integral numbers) "
|
|
"should be left undefined."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:2098
|
|
msgid ""
|
|
"These methods are called to implement the binary arithmetic operations (``"
|
|
"+``, ``-``, ``*``, ``//``, ``%``, :func:`divmod`, :func:`pow`, ``**``, "
|
|
"``<<``, ``>>``, ``&``, ``^``, ``|``). For instance, to evaluate the "
|
|
"expression ``x + y``, where *x* is an instance of a class that has an :meth:"
|
|
"`__add__` method, ``x.__add__(y)`` is called. The :meth:`__divmod__` method "
|
|
"should be the equivalent to using :meth:`__floordiv__` and :meth:`__mod__`; "
|
|
"it should not be related to :meth:`__truediv__` (described below). Note "
|
|
"that :meth:`__pow__` should be defined to accept an optional third argument "
|
|
"if the ternary version of the built-in :func:`pow` function is to be "
|
|
"supported."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:2108
|
|
msgid ""
|
|
"If one of those methods does not support the operation with the supplied "
|
|
"arguments, it should return ``NotImplemented``."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:2115
|
|
msgid ""
|
|
"The division operator (``/``) is implemented by these methods. The :meth:"
|
|
"`__truediv__` method is used when ``__future__.division`` is in effect, "
|
|
"otherwise :meth:`__div__` is used. If only one of these two methods is "
|
|
"defined, the object will not support division in the alternate context; :exc:"
|
|
"`TypeError` will be raised instead."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:2141
|
|
msgid ""
|
|
"These methods are called to implement the binary arithmetic operations (``"
|
|
"+``, ``-``, ``*``, ``/``, ``%``, :func:`divmod`, :func:`pow`, ``**``, "
|
|
"``<<``, ``>>``, ``&``, ``^``, ``|``) with reflected (swapped) operands. "
|
|
"These functions are only called if the left operand does not support the "
|
|
"corresponding operation and the operands are of different types. [#]_ For "
|
|
"instance, to evaluate the expression ``x - y``, where *y* is an instance of "
|
|
"a class that has an :meth:`__rsub__` method, ``y.__rsub__(x)`` is called if "
|
|
"``x.__sub__(y)`` returns *NotImplemented*."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:2152
|
|
msgid ""
|
|
"Note that ternary :func:`pow` will not try calling :meth:`__rpow__` (the "
|
|
"coercion rules would become too complicated)."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:2157
|
|
msgid ""
|
|
"If the right operand's type is a subclass of the left operand's type and "
|
|
"that subclass provides the reflected method for the operation, this method "
|
|
"will be called before the left operand's non-reflected method. This "
|
|
"behavior allows subclasses to override their ancestors' operations."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:2177
|
|
msgid ""
|
|
"These methods are called to implement the augmented arithmetic assignments "
|
|
"(``+=``, ``-=``, ``*=``, ``/=``, ``//=``, ``%=``, ``**=``, ``<<=``, ``>>=``, "
|
|
"``&=``, ``^=``, ``|=``). These methods should attempt to do the operation "
|
|
"in-place (modifying *self*) and return the result (which could be, but does "
|
|
"not have to be, *self*). If a specific method is not defined, the augmented "
|
|
"assignment falls back to the normal methods. For instance, to execute the "
|
|
"statement ``x += y``, where *x* is an instance of a class that has an :meth:"
|
|
"`__iadd__` method, ``x.__iadd__(y)`` is called. If *x* is an instance of a "
|
|
"class that does not define a :meth:`__iadd__` method, ``x.__add__(y)`` and "
|
|
"``y.__radd__(x)`` are considered, as with the evaluation of ``x + y``."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:2196
|
|
msgid ""
|
|
"Called to implement the unary arithmetic operations (``-``, ``+``, :func:"
|
|
"`abs` and ``~``)."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:2211
|
|
msgid ""
|
|
"Called to implement the built-in functions :func:`complex`, :func:`int`, :"
|
|
"func:`long`, and :func:`float`. Should return a value of the appropriate "
|
|
"type."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:2222
|
|
msgid ""
|
|
"Called to implement the built-in functions :func:`oct` and :func:`hex`. "
|
|
"Should return a string value."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:2228
|
|
msgid ""
|
|
"Called to implement :func:`operator.index`. Also called whenever Python "
|
|
"needs an integer object (such as in slicing). Must return an integer (int "
|
|
"or long)."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:2236
|
|
msgid ""
|
|
"Called to implement \"mixed-mode\" numeric arithmetic. Should either return "
|
|
"a 2-tuple containing *self* and *other* converted to a common numeric type, "
|
|
"or ``None`` if conversion is impossible. When the common type would be the "
|
|
"type of ``other``, it is sufficient to return ``None``, since the "
|
|
"interpreter will also ask the other object to attempt a coercion (but "
|
|
"sometimes, if the implementation of the other type cannot be changed, it is "
|
|
"useful to do the conversion to the other type here). A return value of "
|
|
"``NotImplemented`` is equivalent to returning ``None``."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:2249
|
|
msgid "Coercion rules"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:2251
|
|
msgid ""
|
|
"This section used to document the rules for coercion. As the language has "
|
|
"evolved, the coercion rules have become hard to document precisely; "
|
|
"documenting what one version of one particular implementation does is "
|
|
"undesirable. Instead, here are some informal guidelines regarding "
|
|
"coercion. In Python 3, coercion will not be supported."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:2259
|
|
msgid ""
|
|
"If the left operand of a % operator is a string or Unicode object, no "
|
|
"coercion takes place and the string formatting operation is invoked instead."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:2264
|
|
msgid ""
|
|
"It is no longer recommended to define a coercion operation. Mixed-mode "
|
|
"operations on types that don't define coercion pass the original arguments "
|
|
"to the operation."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:2270
|
|
msgid ""
|
|
"New-style classes (those derived from :class:`object`) never invoke the :"
|
|
"meth:`__coerce__` method in response to a binary operator; the only time :"
|
|
"meth:`__coerce__` is invoked is when the built-in function :func:`coerce` is "
|
|
"called."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:2277
|
|
msgid ""
|
|
"For most intents and purposes, an operator that returns ``NotImplemented`` "
|
|
"is treated the same as one that is not implemented at all."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:2282
|
|
msgid ""
|
|
"Below, :meth:`__op__` and :meth:`__rop__` are used to signify the generic "
|
|
"method names corresponding to an operator; :meth:`__iop__` is used for the "
|
|
"corresponding in-place operator. For example, for the operator '``+``', :"
|
|
"meth:`__add__` and :meth:`__radd__` are used for the left and right variant "
|
|
"of the binary operator, and :meth:`__iadd__` for the in-place variant."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:2290
|
|
msgid ""
|
|
"For objects *x* and *y*, first ``x.__op__(y)`` is tried. If this is not "
|
|
"implemented or returns ``NotImplemented``, ``y.__rop__(x)`` is tried. If "
|
|
"this is also not implemented or returns ``NotImplemented``, a :exc:"
|
|
"`TypeError` exception is raised. But see the following exception:"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:2297
|
|
msgid ""
|
|
"Exception to the previous item: if the left operand is an instance of a "
|
|
"built-in type or a new-style class, and the right operand is an instance of "
|
|
"a proper subclass of that type or class and overrides the base's :meth:"
|
|
"`__rop__` method, the right operand's :meth:`__rop__` method is tried "
|
|
"*before* the left operand's :meth:`__op__` method."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:2303
|
|
msgid ""
|
|
"This is done so that a subclass can completely override binary operators. "
|
|
"Otherwise, the left operand's :meth:`__op__` method would always accept the "
|
|
"right operand: when an instance of a given class is expected, an instance of "
|
|
"a subclass of that class is always acceptable."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:2310
|
|
msgid ""
|
|
"When either operand type defines a coercion, this coercion is called before "
|
|
"that type's :meth:`__op__` or :meth:`__rop__` method is called, but no "
|
|
"sooner. If the coercion returns an object of a different type for the "
|
|
"operand whose coercion is invoked, part of the process is redone using the "
|
|
"new object."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:2317
|
|
msgid ""
|
|
"When an in-place operator (like '``+=``') is used, if the left operand "
|
|
"implements :meth:`__iop__`, it is invoked without any coercion. When the "
|
|
"operation falls back to :meth:`__op__` and/or :meth:`__rop__`, the normal "
|
|
"coercion rules apply."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:2324
|
|
msgid ""
|
|
"In ``x + y``, if *x* is a sequence that implements sequence concatenation, "
|
|
"sequence concatenation is invoked."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:2329
|
|
msgid ""
|
|
"In ``x * y``, if one operand is a sequence that implements sequence "
|
|
"repetition, and the other is an integer (:class:`int` or :class:`long`), "
|
|
"sequence repetition is invoked."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:2335
|
|
msgid ""
|
|
"Rich comparisons (implemented by methods :meth:`__eq__` and so on) never use "
|
|
"coercion. Three-way comparison (implemented by :meth:`__cmp__`) does use "
|
|
"coercion under the same conditions as other binary operations use it."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:2341
|
|
msgid ""
|
|
"In the current implementation, the built-in numeric types :class:`int`, :"
|
|
"class:`long`, :class:`float`, and :class:`complex` do not use coercion. All "
|
|
"these types implement a :meth:`__coerce__` method, for use by the built-in :"
|
|
"func:`coerce` function."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:2348
|
|
msgid ""
|
|
"The complex type no longer makes implicit calls to the :meth:`__coerce__` "
|
|
"method for mixed-type binary arithmetic operations."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:2355
|
|
msgid "With Statement Context Managers"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:2359
|
|
msgid ""
|
|
"A :dfn:`context manager` is an object that defines the runtime context to be "
|
|
"established when executing a :keyword:`with` statement. The context manager "
|
|
"handles the entry into, and the exit from, the desired runtime context for "
|
|
"the execution of the block of code. Context managers are normally invoked "
|
|
"using the :keyword:`with` statement (described in section :ref:`with`), but "
|
|
"can also be used by directly invoking their methods."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:2370
|
|
msgid ""
|
|
"Typical uses of context managers include saving and restoring various kinds "
|
|
"of global state, locking and unlocking resources, closing opened files, etc."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:2373
|
|
msgid ""
|
|
"For more information on context managers, see :ref:`typecontextmanager`."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:2378
|
|
msgid ""
|
|
"Enter the runtime context related to this object. The :keyword:`with` "
|
|
"statement will bind this method's return value to the target(s) specified in "
|
|
"the :keyword:`as` clause of the statement, if any."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:2385
|
|
msgid ""
|
|
"Exit the runtime context related to this object. The parameters describe the "
|
|
"exception that caused the context to be exited. If the context was exited "
|
|
"without an exception, all three arguments will be :const:`None`."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:2389
|
|
msgid ""
|
|
"If an exception is supplied, and the method wishes to suppress the exception "
|
|
"(i.e., prevent it from being propagated), it should return a true value. "
|
|
"Otherwise, the exception will be processed normally upon exit from this "
|
|
"method."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:2393
|
|
msgid ""
|
|
"Note that :meth:`__exit__` methods should not reraise the passed-in "
|
|
"exception; this is the caller's responsibility."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:2400
|
|
msgid ":pep:`343` - The \"with\" statement"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:2400
|
|
msgid ""
|
|
"The specification, background, and examples for the Python :keyword:`with` "
|
|
"statement."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:2407
|
|
msgid "Special method lookup for old-style classes"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:2409
|
|
msgid ""
|
|
"For old-style classes, special methods are always looked up in exactly the "
|
|
"same way as any other method or attribute. This is the case regardless of "
|
|
"whether the method is being looked up explicitly as in ``x.__getitem__(i)`` "
|
|
"or implicitly as in ``x[i]``."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:2414
|
|
msgid ""
|
|
"This behaviour means that special methods may exhibit different behaviour "
|
|
"for different instances of a single old-style class if the appropriate "
|
|
"special attributes are set differently::"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:2434
|
|
msgid "Special method lookup for new-style classes"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:2436
|
|
msgid ""
|
|
"For new-style classes, implicit invocations of special methods are only "
|
|
"guaranteed to work correctly if defined on an object's type, not in the "
|
|
"object's instance dictionary. That behaviour is the reason why the "
|
|
"following code raises an exception (unlike the equivalent example with old-"
|
|
"style classes)::"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:2451
|
|
msgid ""
|
|
"The rationale behind this behaviour lies with a number of special methods "
|
|
"such as :meth:`__hash__` and :meth:`__repr__` that are implemented by all "
|
|
"objects, including type objects. If the implicit lookup of these methods "
|
|
"used the conventional lookup process, they would fail when invoked on the "
|
|
"type object itself::"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:2464
|
|
msgid ""
|
|
"Incorrectly attempting to invoke an unbound method of a class in this way is "
|
|
"sometimes referred to as 'metaclass confusion', and is avoided by bypassing "
|
|
"the instance when looking up special methods::"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:2473
|
|
msgid ""
|
|
"In addition to bypassing any instance attributes in the interest of "
|
|
"correctness, implicit special method lookup generally also bypasses the :"
|
|
"meth:`__getattribute__` method even of the object's metaclass::"
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:2500
|
|
msgid ""
|
|
"Bypassing the :meth:`__getattribute__` machinery in this fashion provides "
|
|
"significant scope for speed optimisations within the interpreter, at the "
|
|
"cost of some flexibility in the handling of special methods (the special "
|
|
"method *must* be set on the class object itself in order to be consistently "
|
|
"invoked by the interpreter)."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:2508
|
|
msgid "Footnotes"
|
|
msgstr "Notes"
|
|
|
|
#: ../Doc/reference/datamodel.rst:2509
|
|
msgid ""
|
|
"It *is* possible in some cases to change an object's type, under certain "
|
|
"controlled conditions. It generally isn't a good idea though, since it can "
|
|
"lead to some very strange behaviour if it is handled incorrectly."
|
|
msgstr ""
|
|
|
|
#: ../Doc/reference/datamodel.rst:2513
|
|
msgid ""
|
|
"For operands of the same type, it is assumed that if the non-reflected "
|
|
"method (such as :meth:`__add__`) fails the operation is not supported, which "
|
|
"is why the reflected method is not called."
|
|
msgstr ""
|