我想找到一个干净而聪明的方法(在python中)来查找1s和0s x chars long的字符串的所有排列.理想情况下,这将是快速的,不需要做太多的迭代......
因此,对于x = 1我想要:['0','1'] x = 2 ['00','01','10','11']
等等..
现在我有这个,这很慢,似乎不优雅:
self.nbits = n
items = []
for x in xrange(n+1):
ones = x
zeros = n-x
item = []
for i in xrange(ones):
item.append(1)
for i in xrange(zeros):
item.append(0)
items.append(item)
perms = set()
for item in items:
for perm in itertools.permutations(item):
perms.add(perm)
perms = list(perms)
perms.sort()
self.to_bits = {}
self.to_code = {}
for x in enumerate(perms):
self.to_bits[x[0]] = ''.join([str(y) for y in x[1]])
self.to_code[''.join([str(y) for y in …