编程练习-循环判断（重点是将一个数组的内容给另一个数组）

题目：有一组学生数据，找出其中所有是大一的女生的的名字

　　学生信息如下：

　　(‘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‘)

方法一：

<script>
    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++) {
        if (infos[i][1] === "女" && infos[i][3] === "大一") {
            document.write(infos[i][0] + "<br/>")

        }

    }
</script>

方法二：

  <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 nianJi = new Array(); //重新定义新数组来装满足条件的数组
        var j;
        //第一次筛选，找出都是大一的信息
        for (var i = 0; i < 10; i++) {
            if (infos[i][3] == "大一") {
                nianJi.push(infos[i]);
            }
        }

        // //第二次筛选，找出都是女生的信息
        for (var j = 0; j < nianJi.length; j++) {
            if (nianJi[j][1] == "女") {
                document.write(nianJi[j][0] + "<br>");
            }
        }
    </script>