PHP Modifying the value of an array element in about foreach

PHP supports the use of reference ' & ', the use of the same as C basically, the personal understanding is that the function refers to the variable pointer directly to the source address of the incoming parameter, so using the reference is still a certain danger. Therefore, for a heavy loop, it is recommended that you do not use references to modify the original array directly

        $table _exchange=Array(); Array_push($table _exchange,Array(        "Cnid" = ' 123 ', "status" = 0, "checked" =false, "leaf" =true        )); foreach($table _exchange  as $b=$c)         {            $table _exchange[$b[' Cnid ']= ' 222 '; }        EchoJson_encode ($table _exchange);

Output:

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

In a complex multi-loop operation, the use of references is much easier and easier to understand and manipulate, for example:

         $nodeList=Array(); Array_push($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 $b 2=>&$d){                $d[' Cnid ']= ' 000 '; }        }                EchoJson_encode ($table _exchange);//convert to JSON format output to Web page display results

Output: [{' Cnid ': ' 2 ', ' status ': 0, ' checked ': false, ' children ': [{' Cnid ': ' $ ', ' status ': 1, ' checked ': false, ' leaf ': true}], "Leaf": true}]

PHP Modifying the value of an array element in about foreach