Remove a part of a string, but only when it is at the end of the string

Question

I need to remove a substring of a string, but only when it is at the END of the string.

for example, removing \'string\' at the end of the following strings :

Answer 1

preg_replace and this pattern : /string\z/i

\z means end of the string

http://tr.php.net/preg_replace