PHP正则表达式匹配模式匹配的最后一次出现

Question

I know there is a negative lookahead regex that can match last occurrences of the string.

Example: replace last occurrences of string

I want to do something like this.

Example:

$string = 'hello example (a) hello example (b) (c)';
echo preg_replace('/\(.*?\)(?!.*\(.*?\))/', '', $string);

What I trying to do is to replace the last occurrences of (.*) but I failed. The output I got is hello example . It replaces the entire first ( and the last ) which is (a) hello example (b) (c) .

My expected out put is hello example (a) hello example (b) .

Any one can give some cue? What is the correct regex to achieve what I want. Thank you very much.

Answer 1

You want to use a negated character class here instead of .*? .

The .* inside of your lookahead assertion will match all the way up to the last occurrence of (...) then backtrack consecutively keeping the succession order going.

preg_replace('/\([^)]*\)(?!.*\([^)]*\))/', '', $string);

To simplify this task, just retain everything up until the last occurrence instead.

preg_replace('/.*\K\(.*?\)/', '', $string);

Answer 2

Youre mistake is using \\(.*\\) it's replace full substring which begins whith ( and ends whith ) . .* - max quantificator, (.*) - min quantificator.

Try to use:

$string = 'hello example (a) hello example (b) (c)'; echo preg_replace('/\\((.*)\\)$/', '', $string);