php: trim br tags from the beginning of a string?

Question

I know that:

preg_replace('<br\s*\/?>', '', $string);

will remove all br tags from $string...

How can we remove all <br><br/><br /> tags only if they are in the very beginning of $string? ($string in my case is html code with various tags...)

Answer 1

Just add an appropriate anchor (^):

preg_replace('/^(?:<br\s*\/?>\s*)+/', '', $string);

This will match multiple <br>s at the beginning of the string.

(?:…) is a non-capturing group since we only use the parentheses here to group the expression, not capture it. The modifier isn’t strictly necessary – (…) would work just as well, but the regular expression engine would have to do more work because it then needs to remember the position and length of each captured hit.