$set1 = array('apple', 'banana', 'orange'); $set2 = array('banana', 'grape'); $diff = array_diff($set1, $set2); print_r($diff); //Output: Array ( [0] => apple [2] => orange )In this example, we have two sets ($set1 and $set2) and we want to find the difference between them using the array_diff() function. The resulting array ($diff) contains the elements from $set1 that are not present in $set2, which are 'apple' and 'orange'. The package library for this function is the PHP standard library.