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For example, what is the difference between[\s]and\s?
[\s]
\s
[ab]meansor, one of aorb, representing acharacter set
[ab]
or
character set
abmeansand, aandbappear at the same time, and ab iscontinuous.
ab
and
appear at the same time, and ab is
.
Do you have to ask this kind of question? Do you understand that Baidu can take 5 minutes?
There is no difference between
[s] and s. They both represent space characters
[abc] As long as one of abc appearsabc must be three consecutive abcs
![[Web front-end] Node.js quick start](https://img.php.cn/upload/course/000/000/067/662b5d34ba7c0227.png)
[ab]meansor, one of aorb, representing acharacter setabmeansand, aandbappear at the same time, and ab iscontinuous.Do you have to ask this kind of question? Do you understand that Baidu can take 5 minutes?
There is no difference between
[s] and s. They both represent space characters
[abc] As long as one of abc appears
abc must be three consecutive abcs