3 回答

TA貢獻(xiàn)2條經(jīng)驗(yàn) 獲得超1個(gè)贊
????????????????????????????????????????????????????僅供參考
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?arr1=new?Array();
var?n=0;
for(i=0;i<infos.length;i++){
????if(infos[i][3]=="大一"){//判斷條件只要數(shù)組中是大一學(xué)生的信息
????????arr1[n]=infos[i];//將數(shù)組infos[i]賦給數(shù)組arr1[0]
????????document.write(arr1[n]+"<br/>");
????????n=n+1;//將n+1
????????document.write(n);//這句話寫在n增1之后,輸出結(jié)果沒(méi)有0很正常
????}
????}
????document.write("大一人數(shù):?"+arr1.length+"<br/>");
?/*第一個(gè)循環(huán)過(guò)后arr1的數(shù)組是[?? ['小A','女',21,'大一'],['小D','女',21,'大 一'],['小F','男',21,'大一']['小I','女',20,'大一']? ] */
/*以下循環(huán)為篩選出大一學(xué)生中是女性的學(xué)生*/
for(i=0;i<arr1.length;i++){
????switch(arr1[i][1]){
????????case?'女':????????
????????document.write(arr1[i]+"<br/>");
????????n=n+1;
????}
????}
???

TA貢獻(xiàn)4條經(jīng)驗(yàn) 獲得超0個(gè)贊
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?arr1=new?Array();//定義一個(gè)新的數(shù)組 var?n=0;//定義n之后作為arr里面數(shù)據(jù)的索引值 for(i=0;i<infos.length;i++){ ????if(infos[i][3]=="大一"){//進(jìn)行篩選 ????????arr1[n]=infos[i];//因?yàn)檫@里的i可能是很大的數(shù)字,直接作位arr的索引值會(huì)導(dǎo)致arr變得很長(zhǎng),所以把n作為arr的索引,這時(shí)候n還是0 ????????document.write(arr1[n]+"<br/>"); ????????n=n+1;//n+1變?yōu)? ????????document.write(n); ????} ????} ????document.write("大一人數(shù):?"+arr1.length+"<br/>"); ? ? for(i=0;i<arr1.length;i++){ ????switch(arr1[i][1]){ ????????case?'女': ????????? ????????document.write(arr1[i]+"<br/>"); ????????n=n+1; ????} ????}

TA貢獻(xiàn)4條經(jīng)驗(yàn) 獲得超0個(gè)贊
n是0開(kāi)始的,估計(jì)你輸出的的代碼是寫在n=n+1后面了吧?這個(gè)n就是arr的索引,讓arr的數(shù)據(jù)的索引值是從0到3
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