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                        /前端开发
                        
                            /JavaScript
                        
                        /JavaScript进阶篇

循环筛选和二次筛选

var infos=[["小A","女",21,"大一"],["小B","男",23,"大三"],["小C","男",24,"大四"],["小D","女",21,"大一"],["小E","女",22,"大四"],["小F","男",21,"大一"],["小G","女",22,"大二"],["小H","女",20,"大三"],["小I","女",20,"大一"],["小J","男",20,"大三"]];

var j=0；

var arr=new Array();

for(i=0;i<infos.length;i++)

{

if(infos[i][3]=="大一")

{

document.write(infos[i]+"<br>");

arr[j]=infos[i];

j++;

}

document.write("第二次筛选"+"<br>")

for(i=0;i<arr.length;i++)

{

if(arr[i][1]=="女")

{

document.write(arr[i][0]+"<br>")

}

上面j++去掉之后为什么只能存储最后一次的值

arr[j++]=infos[i]和arr[j]=infos[i];j++一样吗？

如果一样的话 arr[0]里面有数值吗？

艾零

2017-07-01

源自：JavaScript进阶篇 4-10

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2 回答

qq_知秋落葉_0
2017-12-21

var infos=[["小A","女",21,"大一"],["小B","男",23,"大三"],["小C","男",24,"大四"],["小D","女",21,"大一"],["小E","女",22,"大四"],["小F","男",21,"大一"],["小G","女",22,"大二"],["小H","女",20,"大三"],["小I","女",20,"大一"],["小J","男",20,"大三"]];
for (i = 0;i<=infos.length;i++){
    if(infos[i][3] == "大一" && infos[i][1] == "女"){
        document.write(infos[i][0]+"<br/>");
    }
}