Js查漏补缺10-数组、栈、队列、回调函数等 

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>数组与栈</title>
</head>
<body>
<script>

    arr2=[1,2,3];
    document.write(arr2);
<!--数组本质上是一个Object对象-->
    var arr1=new Array(1,2,3);
    document.write(typeof arr1)
    document.write(arr1[0]);
    document.write(arr1.length)


<!--多维数组-->
    var arr3=[[1,2,3],[4,5,6]];
    arr3[2]=[7,8,9];
    document.write(arr3)
    document.write(arr3[2][2])


<!--出栈入栈-->
    var stack_1=["wendy"];
    stack_1.push("red","black");
    document.write(stack_1);
    stack_1.pop();
    document.write(stack_1+"<br>")


<!--入队出队-->
    var queue_1=["wendy"];
    queue_1.push("red","black");
    document.write(queue_1);
    check=queue_1.shift();
    //删除队列第一个元素并返回
    document.write(queue_1);
    document.write(check+"<br>");


<!--遍历数组-->
    var arr5=["a","wendy","red","black"];
    for(var i=0;i<arr5.length;i++)
    {
        console.log(arr5[i]);
    }


<!--forEach回调函数-->
    arr5.forEach(function(value,index,arr){
        document.write(value+"<br>");
        document.write(index+"<br>");
        document.write(arr+"<br>");
    })


<!--sort方法-->
//遍历数组
    var sort_arr=arr5.sort();
    document.write(sort_arr+"<br>");
//带回调函数参数的话可以控制升序降序排列，貌似只能针对数字数组
//对字符数组不起作用，默认升序
    var num_arr=[1,2,3]
    var sort_arr1=num_arr.sort(function(a,b){
        return a-b;//升序
        //return b-a;//降序
    });
    console.log(sort_arr1);

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

 

posted @ 2020-06-19 23:49  Tsui98'  阅读(179)  评论(0)    收藏  举报