regex - Allow only [a-z][A-Z][0-9] in string using PHP

Question

How can I get a string that only contains a to z, A to Z, 0 to 9 and some symbols?

Answer 1

You can filter it like:

$text = preg_replace("/[^a-zA-Z0-9]+/", "", $text);

As for some symbols, you should be more specific