如何转换JavaScript hashmap？

Question

我正在尝试<String, Array()>从json对象创建一个地图.想象一下,我得到了这个json结构:

[
    {
        "userId": "123123",
        "password": "fafafa",
        "age": "21"
    },
    {
        "userId": "321321",
        "password": "nana123",
        "age": "34"
    }
]

我想创建的地图将是:

key(string),value(array)

{
    "userId": [
        "123123",
        "321321"
    ],
    "password": [
        "fafafa",
        "nana123"
    ],
    "age": [
        "21",
        "34"
    ]
}

是否有可能做到这一点？:/

提前致谢.

Answer 1

演示

var json = '[{"userId" : "123123", "password": "fafafa", "age": "21"}, {"userId" : "321321", "password" : "nana123", "age" : "34"}]';

var list = JSON.parse(json);
var output = {};

for(var i=0; i<list.length; i++)
{
    for(var key in list[i])
    {
        if(list[i].hasOwnProperty(key))
        {
            if(typeof output[key] == 'undefined')
            {
                output[key] = [];
            }
            output[key].push(list[i][key]);
        }
    }
}

document.write(JSON.stringify(output));

输出:

{ "用户id":[ "123123", "321321"], "密码":[ "fafafa", "nana123"], "年龄":[ "21", "34"]}