4-10的编程题怎么做 求解
<!DOCTYPE HTML>
<html >
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>流程控制语句</title>
<script type="text/javascript">
//第一步把之前的数据写成一个数组的形式,定义变量为 infos
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,'大二'],
['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']];
//第一次筛选,找出都是大一的信息
//第二次筛选,找出都是女生的信息
for(var i=0;i<infos.length;i++)
{
if(infos[i][3]=='大一' && infos[i][1]=='女')
{
document.write(infos[i][0]+'<br>')
}
}
</script>
</head>
<body>
</body>
</html>
<!DOCTYPE HTML>
<html >
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>流程控制语句</title>
<script type="text/javascript">
//第一步把之前的数据写成一个数组的形式,定义变量为 infos
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,'大二'],
['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']];
//第一次筛选,找出都是大一的信息
//第二次筛选,找出都是女生的信息
for(var i=0;i<infos.length;i++)
{
if(infos[i][3]=='大一' && infos[i][1])
{
document.write(infos[i][0]+'<br>')
}
}
</script>
</head>
<body>
</body>
</html>
<!DOCTYPE HTML>
<html >
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>流程控制语句</title>
<script type="text/javascript">
//第一步把之前的数据写成一个数组的形式,定义变量为 infos
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"]];
//第一次筛选,找出都是大一的信息
var freshmen = new Array();
var j = 0;
for (var i = 0; i < infos.length; i ++){
if (infos[i][3] == "大一"){
freshmen[j++] = infos[i];
}
}
// document.write(freshmen.length);
//第二次筛选,找出都是女生的信息
for (var i = 0; i < j; i ++){
if (freshmen[i][1] == '女'){
document.write(freshmen[i][0] + "<br/>");
}
}
</script>
</head>
<body>
</body>
</html>