在Python中翻转函数的参数顺序 [英] Flipping a function's argument order in Python

问题描述

如今，我开始学习haskell，在我这样做的同时，我尝试用Python来实现从中吸取的一些想法.但是，我发现这一挑战.您可以在Haskell中编写一个函数，该函数将另一个函数用作参数，并返回参数顺序颠倒返回相同的函数.可以在Python中做类似的事情吗?例如，

Nowadays, I am starting to learn haskell, and while I do it, I try to implement some of the ideas I have learned from it in Python. But, I found this one challenging. You can write a function in Haskell, that takes another function as argument, and returns the same function with it's arguments' order flipped. Can one do similiar thing in Python? For example,

def divide(a,b):
    return a / b

new_divide = flip(divide)

# new_divide is now a function that returns second argument divided by first argument

您可以使用Python做到这一点吗?

Can you possibly do this in Python?

推荐答案

您可以使用嵌套函数定义在Python中创建闭包.这样，您就可以创建一个新的函数来颠倒参数顺序，然后调用原始函数:

You can create a closure in Python using nested function definitions. This lets you create a new function that reverses the argument order and then calls the original function:

>>> from functools import wraps
>>> def flip(func):
        'Create a new function from the original with the arguments reversed'
        @wraps(func)
        def newfunc(*args):
            return func(*args[::-1])
        return newfunc

>>> def divide(a, b):
        return a / b

>>> new_divide = flip(divide)
>>> new_divide(30.0, 10.0)
0.3333333333333333

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