For example, what is the difference between [\s] and \s?
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[ab] means or , one of a or b, representing a character set
ab means and , a and b appear at the same time, and ab is continuous.
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
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