循环筛选和二次筛选
来源：4-10 编程练习
艾零
2017-07-01 11:20
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？
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2回答
-
- qq_知秋落葉_0
- 2017-12-21 11:05:44
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/>"); } } -
- 艾零
- 2017-07-01 11:28:29
j++先取j的值 再加1 ++j先取j的值加1
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