【脚本语言系列】关于Python基础知识兼容Python 2.x+Python 3.x，你需要知道的事

如何兼容Python 2.x+Python 3.x

# -*- coding:utf-8 -*-
# For Python 2.x
print print

File "<ipython-input-13-8fe752f7a342>", line 3
print print
^
SyntaxError: invalid syntax

# -*- coding:utf-8 -*-
# For Python 2.x & Python 3.x
from __future__ import print_function

print(print)

<built-in function print>

# -*- coding:utf-8 -*-
# For Python 2.x & Python 3.x
try:
import urllib.request as urllib_request # For Python 3.x
except ImportError:
import urllib2 as urllib_request # For Python 2.x

# -*- coding:utf-8 -*-
# For Python 2.x & Python 3.x
from future.builtins.disabled import *

apply()

---------------------------------------------------------------------------

NameError                                 Traceback (most recent call last)

<ipython-input-15-99a87af09d54> in <module>()
3 from future.builtins.disabled import *
4
----> 5 apply()

c:\python27\lib\site-packages\future\builtins\disabled.pyc in disabled(*args, **kwargs)
55         no longer a builtin in Python 3.
56         '''
---> 57         raise NameError('obsolete Python 2 builtin {0} is disabled'.format(name))
58     return disabled
59

NameError: obsolete Python 2 builtin apply is disabled

什么是兼容Python 2.x+Python 3.x