JavaScript arrays and PHP array traversal comparison Introduction

Both the Javascripe and PHP arrays are of type map, that is, the key value type is not limited. Here I compare the way the two arrays are traversed:
The 1:javascript array traversal uses the in operator, for example, key in Arr, where key is assigned the key in the ARR array and gets value through Arr[key].

    forin arr){        console.log("arr[""] = " + arr[key]);    }

The 2:php array is the use of the as operator, and direct $arr as $k + $v can be used during traversal to place key and value respectively into $k and $V variable.

    $arrarray("k1":"v1","k2":2);    for($arras$k=>$v){        echo$k" = "$v"<br/>";    }

JavaScript arrays and PHP array traversal comparison Introduction