Using Python's max function when you have a va

问题:

Python includes the built in max() function. However, despite it being built in it is not a keyword. That is to say, you are allowed to do max=4. This makes sense since the maximum of something comes up a lot. But! If you use max as a variable, then it disables use of the max function in that scope.

So if you do:

max = 4
max(1, 2)

You will get an error of int object not callable. Again, makes sense. But is there any way to specify that you would like the max function? Like a std.max()? This goes for all other built in functions as well.

回答1:

The __builtin__ (Python 2) / builtins (Python 3) module provides another way to access all built-in/standard identifiers for cases like this:

>>> import __builtin__
>>>
>>> __builtin__.max is max
True
>>>
>>> max = 2
>>> __builtin__.max([0, max])
2

import __builtin__ as builtins

def random_integer(min, max):
    random_integer.seed = builtins.max(10101, ( # looks random enough, right?
        ((random_integer.seed * 3 - 210) % 9898989) >> 1) ^ 173510713571)
    return min + (random_integer.seed % (max - min + 1))

random_integer.seed = 123456789

This module is not normally accessed explicitly by most applications, but can be useful in modules that provide objects with the same name as a built-in value, but in which the built-in of that name is also needed.

The name change in Python 3 is part of the "core languages" changes described in PEP 3100:

In order to get rid of the confusion between __builtin__ and __builtins__, it was decided to rename __builtin__ (the module) to builtins, and to leave __builtins__ (the sandbox hook) alone.