Detecting special characters PHP

Question

I am trying to check whether a string contains any special chars so I know what to do with it afterwards in my script.

Heres what I have:

if (preg_match(         


        

Answer 1

You forgot some escapes:

if (preg_match('/[^A-Z0-9_@£\$¥èéùìòÇØø\+%&\!"#'\(\)\*,
               ^-start string                  ^---end string

Since that's a '-quoted string for the pattern as a whole, all ' inside the pattern MUST be escaped.

Answer 2

You could compare all alphanumeric characters against the string to check if there is any special character:

$temp = '$tack0verflow_';

if(strlen($temp) == strlen(preg_replace("/[^a-zA-Z0-9]+/", "", $temp))){
    // No special characters
} else {
    // Has special characters
}