[英]Merge objects with same key in javascript
如果我有一個像這樣的對象數組,我一直試圖解決這個問題很長一段時間:
var my_array = [
Object {Project: A, Hours: 2},
Object {Project: B, Hours: 3},
Object {Project: C, Hours: 5},
Object {Project: A, Hours: 6},
Object {Project: C, Hours: 9}
]
我想將具有相同鍵的所有對象合並到一個對象中,以便將它們的小時數相加:
預期產量:
my_array = [
Object {Project: A, Hours: 8}
Object {Project: B, Hours: 3}
Object {Project: C, Hours: 14}
]
我該如何處理這個問題? 我花了很長時間才能以這種方式格式化我的數據,這是最后一步!
我的嘗試,我得到我循環數組,不知道如何處理對象的合並:
for (var i =0; i<my_array.length; i++) {
my_array[i].Project // access the object project key
my_array[i].Hours // need to increment hours
}
您可以創建另一個對象,您可以在其中實際對項目進行分組並累積相應的小時數,如下所示
var groups = my_array.reduce(function(resultObject, currentObject) {
// if this is the first time the project appears in the array, use zero as the
// default hours
resultObject[currentObject.Project] = resultObject[currentObject.Project] || 0;
// add the current hours corresponding to the project
resultObject[currentObject.Project] += currentObject.Hours;
return resultObject;
}, {});
此時,您的groups
將如下所示
console.log(groups);
// { A: 8, B: 3, C: 14 }
現在,您只需要擴展此對象,就像這樣
var result = Object.keys(groups).map(function(currentGroup) {
return {Project: currentGroup, Hours: groups[currentGroup]};
});
現在,結果將是
[ { Project: 'A', Hours: 8 },
{ Project: 'B', Hours: 3 },
{ Project: 'C', Hours: 14 } ]
在您的嘗試中 ,您錯過了創建新陣列的過程
var newArray = [];
var uniqueprojects = {};
for (var i =0; i<my_array.length; i++) {
if ( !uniqueproject[my_array[i].Project] )
{
uniqueproject[my_array[i].Project] = 0;
}
uniqueproject[my_array[i].Project] += my_array[i].Hours;
//my_array[i].Project // access the object project key
//my_array[i].Hours // need to increment hours
}
現在從uniqueproject map創建最終輸出數組
newArray = Object.keys(uniqueproject).map(function(key){return {Project:key, Hours:uniqueproject[key]}});
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