Check if variable is a number and positive integer in PHP?

Question

For example, say:

How do I check if variable

Answer 1

use ctype_digit but, for a positive number, you need to add the "> 0" check

if (isset($_GET['p']) && ctype_digit($_GET['p']) && ($_GET['p'] > 0))
{
  // the get input contains a positive number and is safe
}

in general, use ctype_digit in this way

if (ctype_digit((string)$var))

to prevent errors