Question

I have a string to check and if it is only numbers and digits perform another action else exit;

$data = 123412347JB91742F;

 if(preg_match('/[A-Z1-9]/', $data )) {
  echo $data;

} 
else { 
  exit; 
}

this works fine but if I add anything to $data like $ or any other thing it still prints the value. What is wrong with this code?

Edit:

$data = preg_replace('/\-/', '', '1234-1234-JB91-8742F');

if(preg_match('/^[A-Z1-9]+$/', $data )) {
    echo $data;
} else {
    exit;
}

Answer 1

1. Your regex will match every string containing a digit or “normal” character.
2. $data needs to be in quotes.

Your code should look like this:

preg_match('/^[A-Z1-9]+$/', $data)

Do you want to match zeros as well as lower case characters? Then your regex should look like this:

preg_match('/^[A-Z0-9]+$/i', $data)