power.py

# -*- coding: utf-8 -*-
from itertools import chain, tee
from functools import reduce

class powerset(object):
    def __init__(self, orig):
        self._s = list(orig)
        self._b = [False for _ in orig]

    def __iter__(self):
        while True:
            yield list(map(lambda x:x[0], filter(lambda x:x[1], zip(self._s, self._b))))
            try:
                i = self._b.index(False)
                self._b[0:i+1] = [False for _ in range(i+1)]
                self._b[i] = True
            except ValueError:
                raise StopIteration()

def power2(s):
    ps = [0 for _ in s]
    for x in s:
        ps += list(map(lambda z:z+[x], ps)) 
    return ps

if __name__ == '__main__':
    from random import random
    s = list('寝る')
    ps = list(filter(lambda _:random() < 0.5, powerset(s)))
    print(ps)
    if len(ps) == 2**len(s):
        print('寝る冪')
    else:
        print('寝る冪でない')