如果一封信重复出现，就扔掉它

Question

如果一个字母重复出现，有没有办法把它放到字符串中？在

例如，假设我有一个字符串aaardvark，我想去掉其中一个开头的a，我该怎么做？在

Answer 1

下面是一个解决方案，它允许您使用重复字母的不同组合迭代字符串的所有版本：

from itertools import product, groupby

# groups == ['aaaa', 'ppp', 'lll', 'ee']
groups = [''.join(g) for c, g in groupby('aaaappplllee')]

# lengths is an iterator that will return all combinations of string lengths to  
# use for each group, starting with [4, 3, 3, 2] and ending with [1, 1, 1, 1]
lengths = product(*[range(x, 0, -1) for x in map(len, groups)])

# Using the lengths from the previous line, this is a generator that yields all
# combinations of the original string with duplicate letters removed
words = (''.join(groups[i][:v] for i, v in enumerate(x)) for x in lengths)

>>> for word in words:
...   print word
... 
aaaappplllee
aaaapppllle
aaaapppllee
aaaappplle
aaaappplee
aaaappple
...
apple
aplllee
apllle
apllee
aplle
aplee
aple

这不是查找正确单词的最有效的解决方案，但它与OP最初的查找匹配方法是一致的。在