python2
$ workon py2
(py2)$ python
Python 2.7.10 (default, Oct 23 2015, 19:19:21)
[GCC 4.2.1 Compatible Apple LLVM 7.0.0 (clang-700.0.59.5)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import keyword
>>> dir(keyword)
['__all__', '__builtins__', '__doc__', '__file__', '__name__', '__package__',
'iskeyword', 'kwlist', 'main']
>>> keyword.kwlist
['and', 'as', 'assert', 'break', 'class', 'continue', 'def',
'del', 'elif', 'else', 'except', 'exec', 'finally', 'for',
'from', 'global', 'if', 'import', 'in', 'is', 'lambda', 'not',
'or', 'pass', 'print', 'raise', 'return', 'try', 'while',
'with', 'yield']
>>> len(keyword.kwlist)
31
>>> keyword.iskeyword("yield")
Truepython3
$ workon py3 (py3)$ python Python 3.6.5 (v3.6.5:f59c0932b4, Mar 28 2018, 03:03:55) [GCC 4.2.1 (Apple Inc. build 5666) (dot 3)] on darwin Type "help", "copyright", "credits" or "license" for more information. >>> import keyword >>> keyword.kwlist ['False', 'None', 'True', 'and', 'as', 'assert', 'break', 'class', 'continue', 'def', 'del', 'elif', 'else', 'except', 'finally', 'for', 'from', 'global', 'if', 'import', 'in', 'is', 'lambda', 'nonlocal', 'not', 'or', 'pass', 'raise', 'return', 'try', 'while', 'with', 'yield'] >>> len(keyword.kwlist) 33
so：
python2中的关键字：31个
python3中的关键字：33个
比对关键字差异
py2 = ['and', 'as', 'assert', 'break', 'class', 'continue', 'def',
'del', 'elif', 'else', 'except', 'exec', 'finally', 'for',
'from', 'global', 'if', 'import', 'in', 'is', 'lambda', 'not',
'or', 'pass', 'print', 'raise', 'return', 'try', 'while',
'with', 'yield']
py3 = ['False', 'None', 'True', 'and', 'as', 'assert', 'break',
'class', 'continue', 'def', 'del', 'elif', 'else', 'except',
'finally', 'for', 'from', 'global', 'if', 'import', 'in',
'is', 'lambda', 'nonlocal', 'not', 'or', 'pass', 'raise',
'return', 'try', 'while', 'with', 'yield']
print(set(py2) - set(py3))
# {'print', 'exec'}
print(set(py3) - set(py2))
# {'True', 'False', 'None', 'nonlocal'}so：
python2中的
{'print', 'exec'}关键字在python3中已经去除python3中添加了关键字
{'True', 'False', 'None', 'nonlocal'}
