How to extract text started by [duplicate]

How to extract text started by [duplicate]

This question already has an answer here:
How to extract hashtag content? 3 answers
How to extract text started by # (hashtag).
Example:
hello stackoverflow #extractIt and #some
( #extractIt #some )
?
preg_match_all ("/^#[A-Za-z]\d/", $content, $pat_array);