为啥会出现如下情况呢？是不是3.2.2中没有这个函数了，有哪个函数代替cmp()内建函数呀？

Question

>>> a,b = 1,2
>>> a,b
(1, 2)
>>> cmp(a,b)
Traceback (most recent call last):
File "<interactive input>", line 1, in <module>
NameError: name 'cmp' is not defined
>>> 

Answer 1

3开始没这个函数了，官方文档是这么写的The cmp() function should be treated as gone, and the __cmp__() special method is no longer supported. Use __lt__() for sorting, __eq__() with __hash__(), and other rich comparisons as needed. (If you really need the cmp() functionality, you could use the expression (a > b) - (a < b) as the equivalent for cmp(a, b).)大意就是cmp()函数已经“离开”了，如果你真的需要cmp()函数，你可以用表达式(a > b) - (a < b)代替cmp(a,b)