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                        /JavaScript進階篇

循環篩選和二次篩選

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("第二次篩選"+"<br>")

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

? {

? ? ? if(arr[i][1]=="女")

? ? ? {

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

? ? ? }

? }

上面j++去掉之后為什么只能存儲最后一次的值?

arr[j++]=infos[i]和arr[j]=infos[i];j++一樣嗎？

如果一樣的話 arr[0]里面有數值嗎？

艾零

2017-07-01

源自：JavaScript進階篇 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/>");
????}
}