Regex / Preg: No match, if found

Question

I\'m trying to do some PHP preg. But it seems to i can\'t get it to match if i want a string without something in it.

Example:

Hello! My name is [b]Peter         


        

Answer 1

It's unclear what you want to find. If it's just [b]Peter[/b], then you don't need a regex.

If you want to find a single "word" surrounded by BBCode bold tags, use

preg_match('%\[b\]\w*\[/b\]%', $subject)

If you want to find anything within BBCode bold tags as long as it doesn't contain Jack, use

preg_match(
    '%\[b\]     # Match [b]
    (?:         # Try to match...
     (?!Jack)   # (unless the word "Jack" occurs there)
     .          # any character
    )*?         # any number of times, as few as possible
    \[/b\]      # Match [/b]%x', 
    $subject)