用以大写字母开头的单词之间的下划线替换空格的正则表达式语句

Question

输入如下：

Roger Federer is a tennis player. Rafael Nadal Parera is also a tennis player. Another legend player is Novak Djokovic.

我期望得到如下输出：

Roger_Federer is a tennis player. Rafael_Nadal_Parera is also a tennis player. Another legend player is Novak_Djokovic.

我尝试使用正向查找（使用Python re包）的一个解决方案是：

re.sub(r"(?<=\w)\s([A-Z])", r"_\1", above_string)

但是在这里，由于\w，我得到了一个输出：

Roger_Federer is a tennis player. Rafael_Nadal_Parera is also a tennis player. Another legend player is_Novak_Djokovic.

当然，我无法使用r"(?<=[A-Z]\w*)\s([A-Z])"使其工作，因为

error: look-behind requires fixed-width pattern

我必须将这个正则表达式应用于大量（而且非常多样化）的文章，所以我负担不起任何循环或str.replace暴力。我想知道是否有人能提供一个有效的解决方案

Answer 1

如果不关心所有Unicode大写字母，可以使用

import re
above_string = "Roger Federer is a tennis player. Rafael Nadal Parera is also a tennis player. Another legend player is Novak Djokovic."
print( re.sub(r"\b([A-Z]\w*)\s+(?=[A-Z])", r"\1_", above_string) )
# => Roger_Federer is a tennis player. Rafael_Nadal_Parera is also a tennis player. Another legend player is Novak_Djokovic.

见Python demo。见regex demo详细信息：

• \b-单词边界
• ([A-Z]\w*)-group1（\1）：一个大写字母和零个或多个单词字符
• \s+-一个或多个空格
• (?=[A-Z])-与紧跟大写字母的位置匹配的正向前瞻

如果需要支持所有Unicode字母，建议使用pip install regex和

import regex
above_string = "Roger Federer is a tennis player. Rafael Nadal Parera is also a tennis player. Another legend player is Novak Djokovic."
print( regex.sub(r"\b(\p{Lu}\w*)\s+(?=\p{Lu})", r"\1_", above_string) )
# => Roger_Federer is a tennis player. Rafael_Nadal_Parera is also a tennis player. Another legend player is Novak_Djokovic.

见this Python demo。这里，\p{Lu}匹配任何Unicode大写字母