How to remove special characters and keep letters

Question

I know this should remove any characters from string and keep only numbers and ENGLISH letters.

$txtafter = preg_replace("/[^a-zA-Z 0-9]+/","",$txtbefore);

but I wish to remove any special characters and keep any letter of any language like Arabic or Japanese.

Answer 1

Probably this will work for you:

$repl = preg_replace('/[^\w\s]+/u','' ,$txtbefore);

This will remove all non-word and non-space characters from your text. /u flag is there for unicode support.

Answer 2

You can use the \p{L} pattern to match any letter and \p{N} to much any numeric character. Also you should use u modifier like this: /\p{L}+/u

Your final regex may look like: /[^\p{L}\p{N}]/u

Also be sure to check this question:

Regular expression \p{L} and \p{N}