preg_match（）中的分隔符的目的[重复]

Question

This question already has an answer here:

• PHP regex delimiter, what's the point? 3 answers

I understand how to use delimiters in php's preg_match(), just not why I have to use them.

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Answer 1

Delimiters are used to wrap your regular expression. It tells the interpreter which characters make up your regular expression and which characters are relevant flags to modify how the interpreter acts on your regular expression. Other than that, it is simply the way it was implemented.