array push foreach php

$items = array();
foreach($group_membership as $username) {
 $items[] = $username;
}

print_r($items);// array_push ( array &$array [, mixed $... ] ) : int
// array_push() treats array as a stack, and pushes the passed variables onto the end of array. The length of array increases by the number of variables pushed. Has the same effect as:

<?php
$array[] = $var;
?>
// repeated for each passed value.
// Note: If you use array_push() to add one element to the array, it's better to use $array[] = because in that way there is no overhead of calling a function.