很久都不明白。。不明白怎么沒有j了 二維數組比較暈
<!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?infos
?for(var?i=0;i<infos.length;i++)
?{??
?????var?infos[i]=new?Array;
????for(var?j=0;j<4;j++)
????{
????????if(infos[i][3]=="大一")
????????{
????????????if(infos[i][1]=="女")
????????{
?????????document.write("名字是："+infos[i][0]+"<br>");
????????}
????????
????????}
????????
????}
???
?}
?
</script>
</head>
<body>
</body>
</html>去除掉 這兩行var infos[i]=new Array;
? ?????????????????????for(var j=0;j<4;j++)
就正常了，我也看得懂，就是不明白上幾節的時候定義二維數組是要用到mychar[i][j]=i+j；這個為啥不用到j了呢。。。就是為啥子只定義了一個for(var i=0;i<infos.length;i++);就開始用if了，還是說那個infos已經是二維數組就不需要定義了？我轉不過來彎了。。。求各位指點，我比較愚笨。
2016-05-24
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"]]; ?
首先 ?這樣定義 infos ?他就已經是一個二維數組了。 每一個學生的各種信息構成一個數組。 所有的學生又構成令一個數組。?
這里 ?infos[0][0]就代表 “小A”這個字符串 ；?infos[0][1] 就代表“女”這個字符串；以此類推；
比如 我找到所有女生的信息；
就循環每一個學生的信息 如 ?for(i=0;i<infos.length;i++){
if(infos[i][1]=="女"){
? ? ?document.write("學生姓名是"+infos[i][0])
}
}
2016-05-24
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"]];其中第一個for循環是對["小A","女",21,"大一"]這類的進行的，第二個for循環是對["小A","女",21,"大一"]中的元素進行循環的吧
2016-05-24
就是之前的知識點是有提到mychar[j],然后可以用char[i][j],這里面沒有定義infos[j]，怎么就用infos[i][3]了？我知道infos[i][3]的意思，就是不知道要不要再用個[j]來解釋[3]...