JSON-將對象數組轉換成數組對象

Question

我有一系列JSON條目：

[{"num": "1","name_A": "Alex" ,"name_B": "Bob"}, {"num": "2","name_A": "Anne" ,"name_B": "Barbra"}]

我正在嘗試將對象數組盡可能輕松地轉換為兩個對象-一個對象的名稱為name_A，第二個對象的名稱為name_B。 對象必須包含標題和匹配的num-name對數組：

[{title: "name_A", names:[{"1", "Alex}, {"2", "Anne"}]}, {title:"name_B", names: [{"1", "Bob"}, {"2", "Barbra"}]}]

最初，我嘗試通過減少兩次對象數組來簡單地創建兩個對象，一次用於name_A，第二次用於name_B，然后將所有內容粘合在一起：

// get 'names' array
var name_A = objArray.reduce(function(memo, curr) {
    memo.push({curr.num, curr.name_A})
    return memo;
}, []);

但這甚至失敗了。 如果使用空數組初始化reduce，為什么沒有用於備忘錄的push方法？

第二個問題，我是在正確的道路上還是有更好的方法來實現這一目標？

Answer 1

您的代碼的問題是{ curr.num, curr.name_A }不是有效的對象，它缺少屬性名稱。 我在下面的代碼中添加了屬性num和name 。

var name_A = [];
var name_B = [];
objArray.forEach(function(curr) {
    name_A.push({num: curr.num, name: curr.name_a});
    name_B.push({num: curr.num, name: curr.name_B});
});
var result = [ 
    { title: "name_A" }, names: name_A },
    ( title: "name_B" }, names: name_B }
];

另外，如果要根據循環遍歷的結果制作數組，則應使用.map而不是.reduce 。

Answer 2

內聯評論，對預期進行了一些小的更正。

var input = [{ "num": "1", "name_A": "Alex", "name_B": "Bob" }, { "num": "2", "name_A": "Anne", "name_B": "Barbra" }]

var output = input.reduce(function (a, b) {
    // construct new objects and set their properties
    var i = {};
    i[b.num] = b.name_A;
    var j = {};
    j[b.num] = b.name_B;

    // add them to our collection elements
    a[0].names.push(i);
    a[1].names.push(j);

    return a;
   // initializing our collection
}, [{ title: "name_A", names: [] }, { title: "name_B", names: [] }]);

// pretty print our output
console.log(JSON.stringify(output, null, "     "))

 var input = [{ "num": "1", "name_A": "Alex", "name_B": "Bob" }, { "num": "2", "name_A": "Anne", "name_B": "Barbra" }] var output = input.reduce(function (a, b) { // construct new objects and set their properties var i = {}; i[b.num] = b.name_A; var j = {}; j[b.num] = b.name_B; // add them to our collection elements a[0].names.push(i); a[1].names.push(j); return a; // initializing our collection }, [{ title: "name_A", names: [] }, { title: "name_B", names: [] }]); so.log(output) 

 <pre id="output"></pre> <script> var so = { log: function(o) { document.getElementById("output").innerHTML = JSON.stringify(o, null, " ") } } </script> 

Answer 3

假設只有屬性num是固定的。 所有其他屬性都被視為數據，例如name_A或name_B 。

 var a = [{ "num": "1", "name_A": "Alex", "name_B": "Bob" }, { "num": "2", "name_A": "Anne", "name_B": "Barbra" }], result = []; a.forEach(function (el) { var num = el.num; Object.keys(el).forEach(function (k) { function tryFindIndexAndSetNames(aa, i) { if (aa.title === k) { result[i].names[num] = el[k]; return true; } } if (k !== 'num' && !result.some(tryFindIndexAndSetNames)) { var o = {}; o[num] = el[k]; result.push({ title: k, names: o }); } }); }); document.write('<pre>' + JSON.stringify(result, 0, 4) + '</pre>');