这些正则表达式有什么区别 [英] What's the difference between these RegEx

问题描述

1. (\d+|) vs (\d+)?
2. [\w\W] vs [\d\D] vs .

1. (\d+|) vs (\d+)?
2. [\w\W] vs [\d\D] vs .

这些常规正则表达式之间有什么区别吗?应该选择哪一个?

Is there any difference between these regular regex? Which one should be chosen?

我正在使用 JavaScript.

I'm using Javascript.

推荐答案

[\w\W] 和 [\d\D] 用于 JavaScript 等语言其中没有 dotall 选项.它匹配所有字符，包括换行符，不同于 . 匹配所有但换行符.

[\w\W] and [\d\D] are used in languages like JavaScript in which there isn't a dotall option. It matches all characters, including newlines, unlike . which matches everything but a newline.

   \w\W or \d\D   -> matches everything including newline characters
              .   -> matches everything except newline characters unless 
                     's' (dotall modifier) is specified 
(\d+|) or (\d+)?  -> matches 1 or more digits OR any position (null)
                     It could simply be written as '(\d*)'

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