js中 進階4-10編程聯系
<!DOCTYPE??HTML> <html?> <head> <meta?http-equiv="Content-Type"?content="text/html;?charset=utf-8"?/> <title>流程控制語句</title> <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"]]; ?//第一步把之前的數據寫成一個數組的形式,定義變量為 ?var?arr1?=?[]; ???var?n?=?0; ???for(var?i=0;i<infos.length;i++){? ????????if(?infos[i][3]?==?"大一"?){?? ???????????arr1[n]?=?infos[i]; ????????????document.write(arr1[n]+"<br/>"); ???????????n=n+1; ???????????? ????????}?? ???} ??? ???document.write("大一人數:?"+arr1.length+"<br/>");?? ?//第二次篩選,找出都是女生的信息 ??????for(var?i=0;i<arr1.length;i++){? ????????//這里可以用switch?? ????????if(arr1[i][1]=='女') ????????{?document.write(arr1[i][0]+"<br/>");} ????}????? ???? ?//第一次篩選,找出都是大一的信息 ? ?? ?//第二次篩選,找出都是女生的信息 ? ? ?? </script> </head> <body> </body> </html>
關于里面的n=n+1 不是太明白他的意思 輸出infos【i】后相當于輸出了1個數組 既然arr1【n】=infos【i】那么arr1不就是這個數組了嗎?
2016-07-06
有四個人,編號分別是1、2、3、4,每人給一個蘋果。先給了一個給1號,如果給下一個人時,不把編號加1,不就一直給同一個人了嗎
2016-07-06
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<=10;i++){
if(infos[i][3]=="大一"&&infos[i][1]=="女"){
document.write(infos[i][0]+"<br>")
}
}
2016-07-06
他這個是將篩選出來的所有的大一的學生信息全部存放到另一個數組中,就是arr1,相當于用所有大一的學生信息(包括姓名,性別,年齡,年級)初始化arr1數組,再在arr1中篩選性別為 女 的學生的姓名。
2016-07-06
n只是代表數組的下標,也就只是數組的鍵值。
n = n + 1的意義在于當arr[0] = infos[0]之后將n自加,進行下次循環賦值
arr[1] = infos[3];
2016-07-06
arr1也是個數組,它的index=0時,值為arr1[i]的數組.然后n也是要++的.?實際arr1也是個2維數組.