php variable is numeric but returns non numeric error code example

Example 1: check if string is number or not php

$var_num = "1";
$var_str = "Hello World";

var_dump( is_numeric($var_num), is_numeric($var_str) );

/* 
Output -
 bool(true)
 bool(false)
*/

Example 2: php is variable a number

if(is_numeric($what_am_i)){
	//true
}