python cmp import什么模块?

Question

python cmp import什么模块

Answer 1

cmp是Python2.x自带的比较函数，无需import模块。官方手册说明：cmp(x, y)Compare the two objects x and y and return an integer according to theoutcome. &nbsp;The return value is negative if x < y, zero if x == y andstrictly positive if x > y.如下所示：python3.x则取消了这个函数，以下是官方说明：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)

Answer 2

比如你一开始用的:import modulename如果修改的话，要这样：reload(modulename)