future: Easy, safe support for Python 2/3 compatibility

future is the missing compatibility layer between Python 2 and Python 3. It allows you to use a single, clean Python 3.x-compatible codebase to support both Python 2 and Python 3 with minimal overhead.

It is designed to be used as follows::

from __future__ import (absolute_import, division,
                        print_function, unicode_literals)
from builtins import (
         bytes, dict, int, list, object, range, str,
         ascii, chr, hex, input, next, oct, open,
         pow, round, super,
         filter, map, zip)

followed by predominantly standard, idiomatic Python 3 code that then runs similarly on Python 2.6/2.7 and Python 3.3+.

The imports have no effect on Python 3. On Python 2, they shadow the corresponding builtins, which normally have different semantics on Python 3 versus 2, to provide their Python 3 semantics.

Standard library reorganization ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

future supports the standard library reorganization (PEP 3108) through the following Py3 interfaces:

>>> # Top-level packages with Py3 names provided on Py2:
>>> import html.parser
>>> import queue
>>> import tkinter.dialog
>>> import xmlrpc.client
>>> # etc.

>>> # Aliases provided for extensions to existing Py2 module names:
>>> from future.standard_library import install_aliases
>>> install_aliases()

>>> from collections import Counter, OrderedDict   # backported to Py2.6
>>> from collections import UserDict, UserList, UserString
>>> import urllib.request
>>> from itertools import filterfalse, zip_longest
>>> from subprocess import getoutput, getstatusoutput

Automatic conversion

An included script called futurize <http://python-future.org/automatic_conversion.html>_ aids in converting code (from either Python 2 or Python 3) to code compatible with both platforms. It is similar to python-modernize but goes further in providing Python 3 compatibility through the use of the backported types and builtin functions in future.

Documentation

See: http://python-future.org

Credits

:Author: Ed Schofield, Jordan M. Adler, et al :Sponsor: Python Charmers Pty Ltd, Australia, and Python Charmers Pte Ltd, Singapore. http://pythoncharmers.com :Others: See docs/credits.rst or http://python-future.org/credits.html

Licensing

Copyright 2013-2019 Python Charmers Pty Ltd, Australia. The software is distributed under an MIT licence. See LICENSE.txt.

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