創建新的javascript陣列從對象屬性中提取數據

Question

我需要將平面數組轉換爲數組，將相似數據保存在單獨的屬性中，並將數組中的數據字段組合在一起。希望一個例子能夠理解這一點。

原始陣列：

 [{"MtmDate":"2014-10-24", "MouldingID":"1233B", "ID":38, "Mtm01":5.10, "Mtm02":6.63,"Mtm03":5.84 }, 
     {"MtmDate":"2014-10-25", "MouldingID":"1233B", "ID":39, "Mtm01":5.13, "Mtm02":6.21,"Mtm03":6.64 }, 
     {"MtmDate":"2014-10-26", "MouldingID":"1233B", "ID":40, "Mtm01":5.68, "Mtm02":5.95,"Mtm03":6.37 }, 
... 
] 

輸出必需的：

[{"Mtm": 1, values: [{"MtmDate": "2014-10-24", "ID":38, data: 5.10}, 
         {"MtmDate": "2014-10-25", "ID":39, data: 5.13}, 
         {"MtmDate": "2014-10-26", "ID":40, data: 5.68}]}, 
    {"Mtm": 2, values: [{"MtmDate": "2014-10-24", "ID":38, data: 6.63}, 
         {"MtmDate": "2014-10-25", "ID":39, data: 6.21}, 
         {"MtmDate": "2014-10-26", "ID":40, data: 5.95}]}, 
    {"Mtm": 3, values: [{"MtmDate": "2014-10-24", "ID":38, data: 5.84}, 
         {"MtmDate": "2014-10-25", "ID":39, data: 6.64}, 
         {"MtmDate": "2014-10-26", "ID":40, data: 6.37}]}, 
    ] 

我知道我可以通過爲每個數據字段「手動」設置對象，並把它們添加到新的數組執行此：

var mtm1 = { mtm: 1, values: [] }, mtm2 = { mtm: 2, values: [] }, mtm3 = { mtm: 3, values: [] }; 
    var dataByPoint = []; 
    dataByPoint.push(mtm1); 
    dataByPoint.push(mtm2); 
    dataByPoint.push(mtm3); 

然後迭代通過原始數組獲取每個對象的數據：

$.each(d, function(index, value) { 
    var details1 = { mtmDate: value.MtmDate, id: value.ID, data: value.Mtm01 }; 
    if (details1.data) dataByPoint[0].values.push(details1); 

    var details2 = { mtmDate: value.MtmDate, id: value.ID, data: value.Mtm02 }; 
    if (details2.data) dataByPoint[1].values.push(details2); 

    var details3 = { mtmDate: value.MtmDate, id: value.ID, data: value.Mtm03 }; 
    if (details3.data) dataByPoint[2].values.push(details3); 
}); 

但實際上有一打這些數據屬性，這種方法看起來很囉嗦。有沒有辦法通過循環訪問數據屬性來填充新數組？

Answer 1

var arr =[{"MtmDate":"2014-10-24", "MouldingID":"1233B", "ID":38, "Mtm01":5.10, "Mtm02":6.63,"Mtm03":5.84 }, 
 
     {"MtmDate":"2014-10-25", "MouldingID":"1233B", "ID":39, "Mtm01":5.13, "Mtm02":6.21,"Mtm03":6.64 }, 
 
     {"MtmDate":"2014-10-26", "MouldingID":"1233B", "ID":40, "Mtm01":5.68, "Mtm02":5.95,"Mtm03":6.37 } 
 
\t \t ] 
 
\t \t 
 
var newArr = []; \t \t 
 
\t for (var i = 0; i < arr.length; i++) 
 
     { 
 
\t  var obj = {}; 
 
\t  obj.Mtm = (i+1); 
 
\t  obj.values = []; 
 
     if (Object.keys(arr[i])[i+3]) //test if the `Mtm##` is present. 
 
     { 
 
       for (var c = 0; c < arr.length; c++) 
 
       { 
 
        var keys = Object.keys(arr[c]); \t \t 
 
\t   \t obj.values.push({"MtmDate" : arr[c].MtmDate, "ID" : arr[c].ID, "data" : arr[c][keys[i+3]]}); 
 
\t  } 
 
     } 
 
\t  newArr.push(obj); 
 
\t } 
 

 
document.write(JSON.stringify(newArr))

這應該這樣做。它使用兩個循環來解析數據。

外層循環在新數組中創建單個條目，而內層循環解析來自原始元素的所有條目，內容以正確的方式拆分。 Object.keys用於根據循環索引選擇正確的數據元素。

Answer 2

使用數組的map函數。

var originalArray = [{"MtmDate":"2014-10-24", "MouldingID":"1233B", "ID":38, "Mtm01":5.10, "Mtm02":6.63,"Mtm03":5.84 }, 
     {"MtmDate":"2014-10-25", "MouldingID":"1233B", "ID":39, "Mtm01":5.13, "Mtm02":6.21,"Mtm03":6.64 }, 
     {"MtmDate":"2014-10-26", "MouldingID":"1233B", "ID":40, "Mtm01":5.68, "Mtm02":5.95,"Mtm03":6.37 }, 
... 
] 

var expectedArray = originalArray.map(function(v){ 
    return {mtm:v.ID, values:v} 
})