Regexp type for number 0

Question

I want to 0 to 9 any number in input fields,so i check filter_var as below

<?php
$res['pno'] = filter_var($cond['pno'],FILTER_VALIDATE_REGEXP,
//check valid phone no
array('options'=>array('regexp'=>'/^0+[0-9]*$/')))?true:false;                
?>

It is ok when type any number ,But type 0 only ,it return false so how to check it to return true if i type 0 only?

Answer 1

The regexp itself was fine already.

Your actual issue is this:

 ?true:false

When filter_var with the regex succeeds, it will return a string of just "0".

• Now if ?: evaluates that in boolean context, then your final expression will simply be false.

• So wrap your filter_var() result check with strlen() or is_string.

   = is_string(filter_var(…, …, …)) ? true : false;
  

  ^{(Yes, the ?true:false is highly redundant then.)}