Test strings for letters, numbers, and special characters. Returns true if they exist, false if they don't. Forked from http://stackoverflow.com/a/9588010/1293256

has-characters.php

<?php

// Does string contain letters?
function _s_has_letters( $string ) {
    return preg_match( '/[a-zA-Z]/', $string );
}

// Does string contain numbers?
function _s_has_numbers( $string ) {
    return preg_match( '/\d/', $string );
}

// Does string contain special characters?
function _s_has_special_chars( $string ) {
    return preg_match('/[^a-zA-Z\d]/', $string);
}

?>