python:获取给定长度的所有可能字母表
上面没有给出“zzzz”或“zzz”python:获取给定长度的所有可能字母表,python,Python,上面没有给出“zzzz”或“zzz” 我需要下面这样的东西,它可以提供: a、 b,c,d。。 aa,ab,ac。。 aaa,AAAB 但是do_perm()硬编码为循环四次,我不想这样做 def permutations(iterable, r=None): # permutations('ABCD', 2) --> AB AC AD BA BC BD CA CB CD DA DB DC # permutations(range(3)) --> 012 021 10
我需要下面这样的东西,它可以提供: a、 b,c,d。。 aa,ab,ac。。 aaa,AAAB 但是do_perm()硬编码为循环四次,我不想这样做
def permutations(iterable, r=None):
# permutations('ABCD', 2) --> AB AC AD BA BC BD CA CB CD DA DB DC
# permutations(range(3)) --> 012 021 102 120 201 210
pool = tuple(iterable)
n = len(pool)
r = n if r is None else r
if r > n:
return
indices = list(range(n))
cycles = list(range(n, n-r, -1))
yield tuple(pool[i] for i in indices[:r])
while n:
for i in reversed(range(r)):
cycles[i] -= 1
if cycles[i] == 0:
indices[i:] = indices[i+1:] + indices[i:i+1]
cycles[i] = n - i
else:
j = cycles[i]
indices[i], indices[-j] = indices[-j], indices[i]
yield tuple(pool[i] for i in indices[:r])
break
else:
return
got = permutations(getAllTheLetters(),4)
cnt = 0
for i in got:
cnt += 1
print ''.join(i)
print cnt
你可以像这样简单地使用
def getAllTheLetters(begin='a', end='z'):
beginNum = ord(begin)
endNum = ord(end)
yield ''
for number in xrange(beginNum, endNum+1):
yield chr(number)
def do_perm(l):
s = set()
for a in getAllTheLetters():
for b in getAllTheLetters():
for c in getAllTheLetters():
for d in getAllTheLetters():
to_add = "%s%s%s%s" % (a,b,c,d)
if to_add != "":
s.add(to_add)
return s
got = do_perm(1)
cnt = 0
for i in sorted(got):
cnt +=1
print i
print cnt
from itertools import product
def get_strings(letters, max_length):
for i in range(1, max_length + 1):
for value in product(letters, repeat=i):
yield "".join(value)
['a', 'b', 'aa', 'ab', 'ba', 'bb']
当你这样调用它的时候
def getAllTheLetters(begin='a', end='z'):
beginNum = ord(begin)
endNum = ord(end)
yield ''
for number in xrange(beginNum, endNum+1):
yield chr(number)
def do_perm(l):
s = set()
for a in getAllTheLetters():
for b in getAllTheLetters():
for c in getAllTheLetters():
for d in getAllTheLetters():
to_add = "%s%s%s%s" % (a,b,c,d)
if to_add != "":
s.add(to_add)
return s
got = do_perm(1)
cnt = 0
for i in sorted(got):
cnt +=1
print i
print cnt
from itertools import product
def get_strings(letters, max_length):
for i in range(1, max_length + 1):
for value in product(letters, repeat=i):
yield "".join(value)
['a', 'b', 'aa', 'ab', 'ba', 'bb']
你会得到
print(list(get_strings("ab", 2)))
如果要获取从a
到z
的所有值,可以调用get\u strings
,如下所示
def getAllTheLetters(begin='a', end='z'):
beginNum = ord(begin)
endNum = ord(end)
yield ''
for number in xrange(beginNum, endNum+1):
yield chr(number)
def do_perm(l):
s = set()
for a in getAllTheLetters():
for b in getAllTheLetters():
for c in getAllTheLetters():
for d in getAllTheLetters():
to_add = "%s%s%s%s" % (a,b,c,d)
if to_add != "":
s.add(to_add)
return s
got = do_perm(1)
cnt = 0
for i in sorted(got):
cnt +=1
print i
print cnt
from itertools import product
def get_strings(letters, max_length):
for i in range(1, max_length + 1):
for value in product(letters, repeat=i):
yield "".join(value)
['a', 'b', 'aa', 'ab', 'ba', 'bb']
注意:这将创建大量字符串,因此您的计算机可能会停止响应。如果您只想遍历字符串,请使用for
循环get_strings
,如下所示,不要创建列表
from string import ascii_lowercase
print(list(get_strings(ascii_lowercase, 4)))
您需要的是
itertools.compositions\u和\u replacement
,而不是itertools.permutations
。