Question

I have a string which i want to check with a regex. It is not allowed for it to start with a 0. So please see the following examples:

012344 = invalid
3435545645 = valid
021 = invalid
344545 = valid

etc.

How does this regex look in PHP?

PS. This must be a regex solution!

Answer 1

The REGEX should looks like that :

^[1-9][0-9]*$

PHP Code :

<?php

    $regex = "#^[1-9][0-9]*$#";


    function test($value, $regex)
    {
          $text = "invalid";
          if(preg_match($regex, $value)) $text = "valid";
          return $value+" = "+$text+"\n\r";
    }

   echo  test('012345', $regex);
   echo  test('12345', $regex);

?>