array_intersect in PHP

 array_intersect() function generates an array comparing only of those values available in the first input array that also available in each of the other input arrays.

Syntax:  array_intersect(array1,array2,array3...)

Parameters Description:

array1 : Required. The first array will be compared with other arrays.
array2 : Required. An array to be compared with the first array.
array3 : Optional. An array to be compared with the first array.

Example:

<?php
$daysarr1 = array(0=>"Sunday",1=>"Monday",2=>"Tuesday");
$daysarr2 = array(3=>"Tuesday",4=>"Monday",5=>"Thursday");
print_r( array_intersect($daysarr1,$daysarr2) );
?>

O/P:

Array ( 
          [1] => Monday
          [2] => Tuesday
        )