数组案例

1.求一组数中的所有数的和 和平均值

    <script>
        //求一组数中的所有数的和 和平均值
        var scores = [68,88,78,98,80];
        var sum = 0;
        for(var i=0;i<scores.length;i++){
            sum += scores[i];
        }
        console.log(sum);
        console.log(sum/scores.length);
    </script>

2.求一组数中的最大值和最小值，以及所在位置

    <script>
        var scores = [68,88,78,98,80];
        //1.思路
        //首先我们认为数组中第0个数是最大
        var max = scores[0];
        var index = 0;
        for (var i = 1; i < scores.length; i++) {
            if(max < scores[i]){
                index = i;
                max = scores[i];
            }
        }
        console.log(max +";"+ index);
    </script>

3.将字符串数组用|或其他符号分割

var names=["卡卡西","佐助","鸣人","大蛇丸","雏田","小苏","凤姐","黑崎一护"];

    <script>
        var names=["卡卡西","佐助","鸣人","大蛇丸","雏田","小苏","凤姐","黑崎一护"];
        //卡卡西-佐助-鸣人
        var str = "";
        for(var i=0;i<names.length;i++){
            str += names[i];
            if(i != names.length-1){
                str += "-";
            }
        }
        console.log(str);
    </script>

4.要求将数组中的0项去掉，将不为0的值存入一个新的数组，生成新的数组

    <script>
        var s = [0,0,0,11,12,13,14];
        //思路：我们创建一个新的数组，把原来数组中不为0的元素放到新的数组中
        var news = [];
        var b = 0;
        for(var i=0;i<s.length;i++){
            if(s[i] != 0){
                news[b++] = s[i];
            }
        }
        console.log(news);
    </script>

5.反转数组

    <script>
        var s = [1,2,3,4,5,6,7]; 
        for(var i=0;i<parseInt(s.length/2);i++){
            var tmp = s[i];
            s[i] = s[s.length-i-1];
            s[s.length-i-1] = tmp;
        }
        console.log(s);
    </script>

6.提示用户输入班级人数,求总成绩,平均值,最高分,最低分

parseInt(prompt("请输入班级人数"))

    <script>
        var scores = [];
        //count用来限定班级人数(10人)
        var count = 0;
        while(count<10){
            //第几个人的成绩
            var s = parseInt(prompt("请输入第"+count+"个人的分数"));
            scores[count] = s;
            count++;
        }
        console.log(scores);
    </script>