python partial function

刚看到haskell的higher order function 偏函数那一节， 想到python也有这东西， 知道但没看过，就看看

大致的实现是这样的：def partial(func, *args, **keywords): def newfunc(*fargs, **fkeywords): newkeywords = keywords.copy() newkeywords.update(fkeywords) return func(*(args + fargs), **newkeywords) newfunc.func = func newfunc.args = args newfunc.keywords = keywords return newfunc

要使用也很简单的

>>> from functools import partial >>> basetwo = partial(int, base=2) >>> basetwo.__doc__ = 'Convert base 2 string to an int.' >>> basetwo('10010') 18
haskell的则是更好用了，不需要库

multThree :: (Num a) => a -> a -> a -> a multThree x y z = x * y * z ghci> let multTwoWithNine = multThree 9 ghci> multTwoWithNine 2 3 54 ghci> let multWithEighteen = multTwoWithNine 2 ghci> multWithEighteen 10 180