PHP实现删除数组中的特定元素

<?php
2 $arr1 = array(1,3, 5,7,8);
3 $key = array_search(3, $arr1);
4 if ($key !== false)
5     array_splice($arr1, $key, 1);
6 var_dump($arr1);
7 ?>

 <?php
2 $arr2 = array(1,3, 5,7,8);
3 foreach ($arr2 as $key=>$value)
4 {
5     if ($value === 3)
6         unset($arr2[$key]);
7 }
8 var_dump($arr2);
9 ?>