[python]函数式编程

在数据处理过程中经常使用函数式命令，确实能够方便和快捷的实现功能，下面小结一下python实现函数式编程

python提供了lambda、map、filter、reduce和sorted等基础函数进行函数式编程

lamdba

map

map(function, iterable, ...)

    Return an iterator that applies function to every item of iterable, yielding the results. If additional iterable arguments are passed, function must take that many arguments and is applied to the items from all iterables in parallel. With multiple iterables, the iterator stops when the shortest iterable is exhausted. For cases where the function inputs are already arranged into argument tuples, see itertools.starmap().

filter

filter(function, iterable)

    Construct an iterator from those elements of iterable for which function returns true. iterable may be either a sequence, a container which supports iteration, or an iterator. If function is None, the identity function is assumed, that is, all elements of iterable that are false are removed.

    Note that filter(function, iterable) is equivalent to the generator expression (item for item in iterable if function(item)) if function is not None and (item for item in iterable if item) if function is None.

    See itertools.filterfalse() for the complementary function that returns elements of iterable for which function returns false.