javascript对象从键数组获取值数组

Question

我有一个键数组： var keys = ["key1","key2","key3"]和一个对象数组：

var objArr= [
    {"key0":1,"key1":2,"key2":3,"key3":4},
    {"key0":5,"key1":6,"key2":7,"key3":8}
]

我希望能够基于键数组从对象数组中获取值。 例如，其输出将为valueArr = [[2,3,4],[6,7,8]]

我尝试了以下方法：

var result = objArr.map(function(a) {
    for (var i=0;i<keys.length;i++){
        return a[keys[i]];
    };
})

但这返回[2,6]，因为它只是返回它到达的第一个值。 我不确定如何解决它，因此感谢您的帮助！

Answer 1

在数组中推送value并从Array#map返回array

 var keys = ["key1", "key2", "key3"]; var objArr = [{ "key0": 1, "key1": 2, "key2": 3, "key3": 4 }, { "key0": 5, "key1": 6, "key2": 7, "key3": 8 }]; var result = objArr.map(function(a) { var arr = []; for (var i = 0; i < keys.length; i++) { arr.push(a[keys[i]]); }; return arr; }); console.log(result); 

或使用Array#map内Array#map

 var keys = ["key1", "key2", "key3"]; var objArr = [{ "key0": 1, "key1": 2, "key2": 3, "key3": 4 }, { "key0": 5, "key1": 6, "key2": 7, "key3": 8 }]; var result = objArr.map(function(a) { return keys.map(function(key) { return a[key]; }); }); console.log(result); 

Answer 2

不要太早return ，循环只会经历第一个项目：

var result = objArr.map(function(a) {
    var resp = [];
    for (var i=0;i<keys.length;i++){
        resp.push(a[keys[i]]);            
    };
    return resp;
})

Answer 3

作为替代方案 ，你可以使用Object.values()函数，建议在这里 。 例：

var objArr= [
    {"key0":1,"key1":2,"key2":3,"key3":4},
    {"key0":5,"key1":6,"key2":7,"key3":8}
];

for(var i in objArr){
    objArr[i] = Object.values(objArr[i]);
}

不过，目前Internet Explorer，Opera或Safari不支持此功能

Answer 4

您可以使用嵌套的Array#map 。

 var keys = ["key1", "key2", "key3"], objArr = [{ "key0": 1, "key1": 2, "key2": 3, "key3": 4 }, { "key0": 5, "key1": 6, "key2": 7, "key3": 8 }], result = objArr.map(function (a) { return keys.map(function (k) { return a[k]; }); }); console.log(result); 

ES6

 var keys = ["key1", "key2", "key3"], objArr = [{ "key0": 1, "key1": 2, "key2": 3, "key3": 4 }, { "key0": 5, "key1": 6, "key2": 7, "key3": 8 }], result = objArr.map(a => keys.map(k => a[k])); console.log(result); 

Answer 5

您需要将值推送到数组上， return将立即中断执行并返回值。

尝试这个：

var result = objArr.map(function(a) {
    var res = [];
    for (var i=0;i<keys.length;i++){
        res.push(a[keys[i]]);
    };
    return res;
})