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Each step of tranforming code is encapsulated in a fixer. The command ``2to3
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-l`` lists them. As :ref:`documented above <2to3-using>`, each can be turned on
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and off individually. They are described here in more detail.
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Removes usage of :func:`apply`. For example ``apply(function, *args,
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**kwargs)`` is converted to ``function(*args, **kwargs)``.
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.. 2to3fixer:: basestring
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Converts :class:`basestring` to :class:`str`.
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.. 2to3fixer:: buffer
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Converts :class:`buffer` to :class:`memoryview`. This fixer is optional
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because the :class:`memoryview` API is similar but not exactly the same as
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that of :class:`buffer`.
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.. 2to3fixer:: callable
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Converts ``callable(x)`` to ``hasattr(x, "__call_")``.
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Fixes dictionary iteration methods. :meth:`dict.iteritems` is converted to
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:meth:`dict.items`, :meth:`dict.iterkeys` to :meth:`dict.keys`, and
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:meth:`dict.itervalues` to :meth:`dict.values`. It also wraps existing
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usages of :meth:`dict.items`, :meth:`dict.keys`, and :meth:`dict.values` in a
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call to :class:`list`.
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.. 2to3fixer:: except
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Converts ``except X, T`` to ``except X as T``.
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Converts the :keyword:`exec` statement to the :func:`exec` function.
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.. 2to3fixer:: execfile
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Removes usage of :func:`execfile`. The argument to :func:`execfile` is
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wrapped in calls to :func:`open`, :func:`compile`, and :func:`exec`.
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.. 2to3fixer:: filter
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Wraps :func:`filter` usage in a :class:`list` call.
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.. 2to3fixer:: funcattrs
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Fixes function attributes that have been renamed. For example,
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``my_function.func_closure`` is converted to ``my_function.__closure__``.
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.. 2to3fixer:: future
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Removes ``from __future__ import new_feature`` statements.
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.. 2to3fixer:: getcwdu
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Renames :func:`os.getcwdu` to :func:`os.getcwd`.
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.. 2to3fixer:: has_key
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Changes ``dict.has_key(key)`` to ``key in dict``.
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.. 2to3fixer:: idioms
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This optional fixer preforms several transformations that make Python code
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more idiomatic. Type comparisions like ``type(x) is SomeClass`` and
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``type(x) == SomeClass`` are converted to ``isinstance(x, SomeClass)``.
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``while 1`` becomes ``while True``. This fixer also tries to make use of
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:func:`sorted` in appropiate places. For example, this block ::
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L = list(some_iterable)
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L = sorted(some_iterable)
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.. 2to3fixer:: import
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Detects sibling imports and converts them to relative imports.
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.. 2to3fixer:: imports
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Handles module renames in the standard library.
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.. 2to3fixer:: imports2
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Handles other modules renames in the standard library. It is separate from
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the :2to3fixer:`imports` fixer only because of technical limitations.
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Converts ``input(prompt)`` to ``eval(input(prompt))``
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.. 2to3fixer:: intern
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Converts :func:`intern` to :func:`sys.intern`.
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.. 2to3fixer:: isinstance
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Fixes duplicate types in the second argument of :func:`isinstance`. For
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example, ``isinstance(x, (int, int))`` is converted to ``isinstance(x,
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.. 2to3fixer:: itertools_imports
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Removes imports of :func:`itertools.ifilter`, :func:`itertools.izip`, and
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:func:`itertools.imap`. Imports of :func:`itertools.ifilterfalse` are also
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changed to :func:`itertools.filterfalse`.
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.. 2to3fixer:: itertools
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Changes usage of :func:`itertools.ifilter`, :func:`itertools.izip`, and
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:func:`itertools.imap` to their built-in equivalents.
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:func:`itertools.ifilterfalse` is changed to :func:`itertools.filterfalse`.
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Strips the ``L`` prefix on long literals and renames :class:`long` to
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Wraps :func:`map` in a :class:`list` call. It also changes ``map(None, x)``
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to ``list(x)``. Using ``from future_builtins import map`` disables this
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.. 2to3fixer:: metaclass
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Converts the old metaclass syntax (``__metaclass__ = Meta`` in the class
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body) to the new (``class X(metaclass=Meta)``).
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.. 2to3fixer:: methodattrs
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Fixes old method attribute names. For example, ``meth.im_func`` is converted
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to ``meth.__func__``.
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Converts the old not-equal syntax, ``<>``, to ``!=``.
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Converts the use of iterator's :meth:`~iterator.next` methods to the
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:func:`next` function. It also renames :meth:`next` methods to
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:meth:`~object.__next__`.
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.. 2to3fixer:: nonzero
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Renames :meth:`~object.__nonzero__` to :meth:`~object.__bool__`.
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.. 2to3fixer:: numliterals
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Converts octal literals into the new syntax.
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Add extra parenthesis where they are required in list comprehensions. For
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example, ``[x for x in 1, 2]`` becomes ``[x for x in (1, 2)]``.
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Converts the :keyword:`print` statement to the :func:`print` function.
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.. 2to3fixer:: raises
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Converts ``raise E, V`` to ``raise E(V)``, and ``raise E, V, T`` to ``raise
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E(V).with_traceback(T)``. If ``E`` is a tuple, the translation will be
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incorrect because substituting tuples for exceptions has been removed in 3.0.
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.. 2to3fixer:: raw_input
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Converts :func:`raw_input` to :func:`input`.
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.. 2to3fixer:: reduce
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Handles the move of :func:`reduce` to :func:`functools.reduce`.
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.. 2to3fixer:: renames
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Changes :data:`sys.maxint` to :data:`sys.maxsize`.
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Replaces backtick repr with the :func:`repr` function.
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.. 2to3fixer:: set_literal
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Replaces use of the :class:`set` constructor with set literals. This fixer
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.. 2to3fixer:: standard_error
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Renames :exc:`StandardError` to :exc:`Exception`.
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.. 2to3fixer:: sys_exc
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Changes the deprecated :data:`sys.exc_value`, :data:`sys.exc_type`,
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:data:`sys.exc_traceback` to use :func:`sys.exc_info`.
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Fixes the API change in generator's :meth:`throw` method.
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.. 2to3fixer:: tuple_params
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Removes implicit tuple parameter unpacking. This fixer inserts temporary
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Fixes code broken from the removal of some members in the :mod:`types`
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.. 2to3fixer:: unicode
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Renames :class:`unicode` to :class:`str`.
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.. 2to3fixer:: urllib
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Handles the rename of :mod:`urllib` and :mod:`urllib2` to the :mod:`urllib`
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.. 2to3fixer:: ws_comma
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Removes excess whitespace from comma separated items. This fixer is
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.. 2to3fixer:: xrange
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Renames :func:`xrange` to :func:`range` and wraps existing :func:`range`
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calls with :class:`list`.
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.. 2to3fixer:: xreadlines
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Changes ``for x in file.xreadlines()`` to ``for x in file``.
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Wraps :func:`zip` usage in a :class:`list` call. This is disabled when
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``from future_builtins import zip`` appears.
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:mod:`lib2to3` - 2to3's library
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-------------------------------
added
removed
Doc/library/2to3.rst
