需要匹配PHP正则表达式中的多个反斜杠

Question

I'm trying to match 4 backslahes using preg_match.

preg_match('/\\\\\\\\/',$subject) works fine, but preg_match('/\\{4}/',$subject) doesn't.

Perhaps I'm using {} incorrectly. Could anyone advise?

Answer 1

Ok I got it: Two backslashes mean you want one backslash in your string: So for the regex it looks like this: /\{4}/ Which means you want to escape the {

What you need here is:

preg_match('/\\\\{4}/', $subject);

That looks for the regex like this: /\\{4}/ and works properly.