how to put onto end of array php code example

Example 1: php add item to array

<?php
  $z = ['me','you', 'he'];
  array_push($z, 'she', 'it');
  print_r($z);
?>

Example 2: array push in php

$cart = array();
$cart[] = 13;
$cart[] = 14;
// etc

//Above is correct. but below one is for further understanding
$cart = array();
for($i=0;$i<=5;$i++){
    $cart[] = $i;  
}
echo "<pre>";
print_r($cart);
echo "</pre>";