php how to check string contain only whole number code example

Example 1: php check if string or number

<?php if (is_numeric(887)) { echo "Yes"; } else { echo "No"; } ?>

Example 2: php check if string or number

<?php if (is_numeric("cake")) { echo "Yes"; } else { echo "No"; } ?>

Example 3: php check if string contains number

if (preg_match('/[A-Za-z]/', $myString) && preg_match('/[0-9]/', $myString))
{
    echo 'Contains at least one letter and one number';
}