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(var?i=0;i<infos.length;i++){
???? var?n?=?0;
???? var?arr=[];
????switch(infos[i][3]){
???? case?"大一":
???? ??arr[n]=infos[i][3];
???? ??break;
???? ??default:
???? ??document.write("<br>");
???? ??n++;
????}}
????for(var?j=0;j?<arr.length;j++){
????? switch(arr[j][1]){
????? case?"女":
????? document.write(arr[j][0]);
????? break;
????? default:
???? ????document.write("<br>");
????? }
????}
2017-05-28
<!DOCTYPE??HTML> <html?> <head> <meta?http-equiv="Content-Type"?content="text/html;?charset=utf-8"?/> <title>流程控制語(yǔ)句</title> </head> <body> <script?type="text/javascript"> 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?n?=?0;?var?arr=[]; ????for(var?i=0;i<infos.length;i++){ ??????? ??????? ????switch(infos[i][3]){ ????????case?"大一": ??????????arr[n]=infos[i]; ??????????n++; ??????????console.log(n); ??????????break; ??????????default: ??????????document.write("<br>"); ?? ????????? ????}}; ????console.log(arr.length); ????for(var?j=0;j?<arr.length;j++){ ???????switch(arr[j][1]){ ???????????case?'女': ???????????document.write(arr[j][0]+"<br>"); ???????????break; ???????????default: ????????????document.write("<br>"); ?????????? ???????} ????} ?? </script> </body> </html>2017-06-23
jojo
2017-05-28
問題還是蠻多的，例如后面你想再次判斷arr[j][1]，那么就要給arr賦值的時(shí)候也是一個(gè)二維數(shù)組，arr[n]=infos[i];例如這個(gè)，而且我覺得你的n++可能放的位置不對(duì)，會(huì)影響arr的數(shù)組的長(zhǎng)度。n和arr都需要在循環(huán)外定義，不然每次都會(huì)重新定義一次，相當(dāng)與重新初始化了