创建一个详尽的'n`子串列表(Creating an exhaustive list of `n` substrings)

创建一个详尽的'n`子串列表(Creating an exhaustive list of `n` substrings)

我正在训练将一个字符串拆分为n个子串并返回它们的元组列表。

我现在使用for (w1,w2) in [(w[:i],w[i:]) for i in range(len(w))]代码for (w1,w2) in [(w[:i],w[i:]) for i in range(len(w))]其中w是包含单词的变量。 因此，如果w='house'那么这将返回[('','house'),('h','ouse')等。

这非常适合将字符串拆分成所有可能的字符串对，但现在我想进行其他分割（例如n=3 ）字符串，例如'ho','u','se'将单个字符串拆分为全部n子串的可能方式。 我怎样才能有效地做到这一点？

I am training to split a string into n substrings and return a list of tuples of them.

I now use the code for (w1,w2) in [(w[:i],w[i:]) for i in range(len(w))] where w is the variable which contains the word. So if w='house' then this will return [('','house'),('h','ouse') etc..

This works perfectly for splitting a string into all possible pairs of strings, but now I want to make other splits (e.g. n=3) of strings such as 'ho','u','se' which split a single string into all possible ways of n substrings. How can I do that efficiently?

最满意答案

以下是使用生成器递归执行此操作的一种方法：

def split_str(s, n): if n == 1: yield (s,) else: for i in range(len(s)): left, right = s[:i], s[i:] for substrings in split_str(right, n - 1): yield (left,) + substrings for substrings in split_str('house', 3): print substrings

打印出：

('', '', 'house') ('', 'h', 'ouse') ('', 'ho', 'use') ('', 'hou', 'se') ('', 'hous', 'e') ('h', '', 'ouse') ('h', 'o', 'use') ('h', 'ou', 'se') ('h', 'ous', 'e') ('ho', '', 'use') ('ho', 'u', 'se') ('ho', 'us', 'e') ('hou', '', 'se') ('hou', 's', 'e') ('hous', '', 'e')

如果您不想要空字符串，请将循环边界更改为

for i in range(1, len(s) - n + 2):

Here is one way to do this, recursively, using a generator:

def split_str(s, n): if n == 1: yield (s,) else: for i in range(len(s)): left, right = s[:i], s[i:] for substrings in split_str(right, n - 1): yield (left,) + substrings for substrings in split_str('house', 3): print substrings

This prints out:

('', '', 'house') ('', 'h', 'ouse') ('', 'ho', 'use') ('', 'hou', 'se') ('', 'hous', 'e') ('h', '', 'ouse') ('h', 'o', 'use') ('h', 'ou', 'se') ('h', 'ous', 'e') ('ho', '', 'use') ('ho', 'u', 'se') ('ho', 'us', 'e') ('hou', '', 'se') ('hou', 's', 'e') ('hous', '', 'e')

If you don't want the empty strings, change the loop bounds to

for i in range(1, len(s) - n + 2):