Question

I need to remove all occurances of a string but only when it is within 2 tags.

For example in the content below I need to remove both occurances of foo within the [bar][/bar] tags.

foo
foo
[bar]
foo bar foo
[/bar]
foo

I am using PHP and I would like to find a solution which doesn’t involve 2 steps (ie search for the content between [bar][/bar] first and then do the replace). If this is not possible then no problem, any help is much appreciated!

Answer 1

If your tags are all well formed and not nested you may be successful with this

\bfoo\b(?=[^\[]*\[\/bar\])

See it here on Regexr

It searches for foo surrounded by word boundaries \b (foo in foobar will not match), that is followed by a closing tag [/bar]. to ensure that there is no new opening tag I will only match characters other than [ with [^\[]*.

(?=[^\[]*\[\/bar\]) is a lookahead assertion that does not match it only looks ahead if the pattern inside is following.