函数参数为数组时传值、传址的区别，请高手结合实例讲解-PHP Tutorial-php.cn

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函数参数为数组时传值、传址的区别，请高手结合实例讲解

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Jun 20, 2016 pm 12:37 PM

回复讨论(解决方案)

值传递：
拷贝一份原始数据进行操作，不改变原值。
引用传递：
操作原始数据，操作过后原始数据会改变。

数组值传递实例代码：<?phpfunction main() {        $cc = array(            'a','b'        );        change($cc);        var_dump($cc);        die;}function change($cc){        $cc = array('dd');}main();?>output:array(2) {  [0]=>  string(1) "a"  [1]=>  string(1) "b"}数组引用传递<?phpfunction main() {        $cc = array(            'a','b'        );        change($cc);        var_dump($cc);        die;}function change(&$cc){        $cc = array('dd');}main();?>outpout:array(1) {  [0]=>  string(2) "dd"}

参考这个看看吧：http://www.cnblogs.com/zcy_soft/archive/2011/12/10/2283570.html

$res[] = $v;
if($t) foo($t, $level+1, $v['id'], $res)
----这两个语句在函数 foo 内部，但原理是一样的。如同楼上所举的例子

传值不会影响原数组，传地址会。
例子：
地址引用

<?php$arr = array(1,2,3,4,5);pop($arr);print_r($arr);function pop(&$arr){    array_pop($arr);}?>

输出：
Array ( [0] => 1 [1] => 2 [2] => 3 [3] => 4 )

传值

<?php$arr = array(1,2,3,4,5);$arr1 = pop($arr);print_r($arr);print_r($arr1);function pop($arr){    array_pop($arr);    return $arr;}?>

输出：
Array ( [0] => 1 [1] => 2 [2] => 3 [3] => 4 [4] => 5 )
Array ( [0] => 1 [1] => 2 [2] => 3 [3] => 4 )

说白了就是，函数的参数，默认都是复制一份的，这样你函数内怎么折腾都不会影响到使用函数时传过来的变量
加上&就不会复制，而直接用了

传值就是多复制一份，相互不影响
引用就是同时操作同一份数据，相互影响

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