regex - Remove everything except letters from PHP string

Question

How can I remove everything from a string apart from letters? I have an input field for first names.

Answer 1

In PHP, you can use (as suggested by @rczajka and @mario):

preg_replace('/PL/u', '', $str)

Working Example: http://codepad.viper-7.com/V78skl

You may want to checkout this Tutorial for regex