PHP 關於foreach 中修改array中元素的值

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PHP中支援使用引用‘&‘，用法與C基本一樣，個人理解就是函數中引用的變數指標直接指向了傳入參數的源地址，所以使用引用還是存在一定的危險性。所以對於一重迴圈，建議不使用引用，直接修改原array即可

        $table_exchange=array();        array_push($table_exchange, array(        "cnid" => ‘123‘,        "status" =>  0,        "checked" => false,        "leaf" => true        ));        foreach ($table_exchange as $b=> $c)         {            $table_exchange[$b][‘cnid‘]= ‘222‘;        }        echo json_encode($table_exchange);

輸出：

[{"cnid":"222","status":0,"checked":false,"leaf":true}]

而在操作複雜的多重迴圈中，使用引用會方便許多，也更加便於理解和操作，例如：

         $nodeList=array();        array_push($nodeList, array(        "cnid" => ‘1‘,        "status" =>  1,        "checked" => false,        "leaf" => true        ));        $table_exchange=array();        array_push($table_exchange, array(        "cnid" => ‘2‘,        "status" =>  0,        "checked" => false,        "children" => $nodeList,        "leaf" => false        ));                foreach ($table_exchange as $b=>& $c){                        foreach($c[‘children‘] as $b2=>& $d){                $d[‘cnid‘]=‘000‘;            }        }                echo json_encode($table_exchange);//轉成json格式輸出到網頁顯示結果

輸出：[{"cnid":"2","status":0,"checked":false,"children":[{"cnid":"000","status":1,"checked":false,"leaf":true}],"leaf":true}]

PHP 關於foreach 中修改array中元素的值