python - 使用 re.sub() 的输出不正确

Question

问题陈述:

Inserts an extra space after a period if the period is directly followed by a letter.

下面是代码:

string="This   is  very funny  and    cool.Indeed!"

re.sub("\.[a-zA-Z]", ". ", string)

和输出:

"This is very funny and cool. ndeed!"

它正在替换 '.' 之后的第一个字符。

有什么解决办法吗？

Answer 1

您可以使用positivie lookahead assertion ，它不消耗匹配的部分:

>>> re.sub(r"\.(?=[a-zA-Z])", ". ", string)
'This   is  very funny  and    cool. Indeed!'

替代使用 capturing group and backreference :

>>> re.sub(r"\.([a-zA-Z])", r". \1", string)  # NOTE - r"raw string literal"
'This   is  very funny  and    cool. Indeed!'

仅供引用，您可以使用 \S 而不是 [a-zA-Z] 来匹配非空格字符。