php multi byte strings regex

Question

We have a regex to strip out non alpha numeric characters except for '#', '&' and '-'. Here is what it looks like:

preg_replace('/[^a-zA-Z0-9#&-*]/', '', strtolower($title));

Now we need to support traditional Chinese strings and the above function won't work. How can I implement similar functionality for traditional Chinese.

Thanks,

Answer 1

Use u modifier:

preg_replace(`/[^a-zA-Z0-9#&-*诶]/u`, '', $string);

By the way, don't use strtolower(), because it will break your string. Use mb_strtolower():

mb_strtolower($string, 'UTF-8');