Question

In PHP, I want to get all the tags (e.g. @Joe) in a string, but avoid email address (e.g. [e-mail]).

So in:

@Joe hello! @Dave's email address is [e-mail]

I want to only match @Joe and @Dave .

The regex I’m trying is

preg_match_all("([ ^]@[a-zA-Z0-9]+)", $comment, $atMatches); 

But this only matches @Dave (after removing leading space).

Answer 1

You could use the \B (not a word boundry) escape sequence to exclude the matches that have a word (like “dave” in the example text) before it. Something like:

preg_match_all("/\B(@[a-zA-Z0-9]+)/", $comment, $atMatches); 

By the way, you’re not using proper delimiters in your syntax.