How to match a pound (#) symbol in a regex in php (for hashtags)

Question

Very simple, I need to match the # symbol using a regex. I\'m working on a hashtag detector.

I\'ve tried searching in google and in stack overflow. One

Answer 1

With the comment on the earlier answer, you want to avoid matching x#x. In that case, your don't need \b but \B:

\B#(\w\w+)

(if you really need two-or-more word characters after the #).

The \B means NON-word-boundary, and since # is not a word character, this matches exactly if the previous character is not a word character.