js将数组转化为一个对象obj，将数组中的内容作为对象的key转化为对象，将数组中的某项内容作为分类来转成对象

蔚落 2023-06-07 10:35 102阅读 0赞

1.js数组转成对象

var list = {};
    var arr = ["123","456","789"];
    // for in 循环
    for (var key in arr) {
        list[key] = arr[key];
    }
    console.log(list); //控制台打印

打印如下  
![在这里插入图片描述][20191014110639515.png]  
我的思路就是这样，不止这一种其他循环也可以forEach、map、reduce等等

2.将数组中的内容作为对象的key转化为对象

//数组
    var formArr =  [
    {name: "张三", num: "1"},
    {name: "李四", num: "2"},
    {name: "王二", num: "3"},
    {name: "麻子", num: "4"}
    ];
    
    //创建对象
    var obj={ };
    
    //map循环方式
      formArr.map(function (e, item) {
      obj[e.num] = e.name;
      });
    console.log(obj); //控制台打印

结果打印：obj = \{1: “张三”, 2: “李四”, 3: “王二”, 4: “麻子”\}  
不止这一种其他循环也可以forEach、for in、reduce等等

3.将数组中的某项内容作为分类来转成对象  
例如页面上有个小组(group)成员，点击那个小组显示那个小组的成员

//数组
    var formArr =  [
    {name: "张三", group: "1"},
    {name: "李四", group: "1"},
    {name: "王二", group: "2"},
    {name: "麻子", group: "2"},
    {name: "小明", group: "3"},
    {name: "小红", group: "3"},
    {name: "隔壁", group: "4"},
    {name: "老王", group: "4"}
    ];
    
    //创建对象
    let obj = {}
    
    //forEach循环
    formArr.forEach(item => {
        if (!obj[item.group]) {
          obj[item.group] = [item]
        } else {
          obj[item.group].push(item)
        }
      })
    console.log(obj) //控制台打印

结果打印：  
![在这里插入图片描述][20191014113940857.png]  
展开  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L1pfa2Vuc2hvdQ_size_16_color_FFFFFF_t_70]  
然后在页面上循环展示即可

[20191014110639515.png]: /images/20230601/921f5fda62ab4a87b01ab72842bf4e55.png
[20191014113940857.png]: /images/20230601/de36b1f8a62e4fc896281d34c66cc0eb.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L1pfa2Vuc2hvdQ_size_16_color_FFFFFF_t_70]: /images/20230601/7b8ca1c134794de3a956cc51ca7dac90.png