is_numeric() in php

is_numeric is used to find a variable is number or string

Example:

index.php

<?php
//numeric check
 if (is_numeric (8))
 {
     echo "Yes";
 }
 else {
     echo "No";
 }
 ?>
 8 is a number,then should result is "Yes"

<?php
 //No-numeric check
 if (is_numeric ("test"))
 {
     echo "Yes";
 }
 else
 {
     echo "No";
 }
 ?>
Test is not a number,then should result is "No"