php only allow letters, numbers, spaces and specific symbols using pregmatch

Question

on my php i use preg_match to validate input texts.

if(preg_match(\'/^[a-zA-Z0-9]+$/\', $firstname)) {
}

But this only allows alp

Answer 1

Use

preg_match('/^[a-z0-9 .\-]+$/i', $firstname)

Answer 2

The only difficult bit here is the dash.

For spaces and dots, you can simply add them to your character class, like so:

'/^[a-zA-Z0-9 .]+$/'

Easy.

The dash is slightly harder because hyphens have special meaning in a character class like this (as you already know, they're used for ranges of characters like a-z). In order to specify a hyphen in a character class, it must be the first character in the class (ie it must not be between two characters, otherwise it is treated as a character range marker).

So your expression would be:

'/^[-a-zA-Z0-9 .]+$/'

Hope that helps.

Answer 3

If you not only want to allow ASCII, then use Unicode properties:

preg_match('/^[\p{L}\p{N} .-]+$/', $firstname)

\p{L} is any letter in any language, matches also Chinese, Hebrew, Arabic, ... characters.

\p{N} any kind of numeric character (means also e.g. roman numerals)

if you want to limit to digits, then use \p{Nd}