<?php
//using end() function to find last array key changes the array pointer, which can cause problems.

$array = array('a' => 1, 'b' => 2, 'c' => 3, 'd' => 2);
// Get array keys
$arrayKeys = array_keys($array);
// Fetch last array key
$lastArrayKey = array_pop($arrayKeys);
//iterate array
foreach($array as $k => $v) {
    if($k == $lastArrayKey) {
        //during array iteration this condition states the last element.
    }
}
?>