list reduce 

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Document</title>



    <script>
        let arr = [12,44,22,54,52];

        let res=arr.reduce(function (tmp,item,index){
            alert(`第${index}次,${tmp}+${item}`);
            return tmp+item;
        });


    </script>
</head>
<body>
    
</body>
</html>

 

 

 

 

<script>
        let arr = [12,44,22,54,52];

        let res=arr.reduce(function (tmp,item,index){
            if (index < arr.length-1){
                return tmp+item;
            }else{
                return (tmp+item)/arr.length;
            }
            
        });
        alert(res);

    </script>

 

posted @ 2021-02-05 22:28  AngDH  阅读(237)  评论(0)  编辑  收藏  举报