Detailed explanation of pushing and popping linear tables in PHP

<?php 
$stack = array("Simon", "Elaine"); //定义数组 
array_push($stack, "Helen", "Peter"); //入栈 
print_r($stack); 
?>

<?php 
$stack = array("Simon", "Elaine"); //定义数组 
array_unshift ($stack, "Helen", "Peter"); //入栈 
print_r($stack); 
?>

<?php 
$stack = array("Simon", "Elaine", "Helen", "Peter"); 
echo array_pop($stack)."/n"; //出栈 
print_r($stack); 
?>

<?php 
$stack = array("Simon", "Elaine", "Helen", "Peter"); 
echo array_shift($stack)."/n"; //出栈 
print_r($stack); 
?>