數組映射，將數組映射為數組的鍵

Question

我知道標題可能聽起來令人困惑，但是使用$ .each卻花了一個小時。 基本上我有2個數組

[{"section_name":"abc","id":1},{"section_name":"xyz","id":2}];

和[{"toy":"car","section_id":1},{"tool":"knife","section_id":1},{"weapons":"cutter","section_id":2}];

我如何將它們作為新的屬性密鑰放入另一個

[{
    "section_name": "abc",
    "id": 1,
    "new_property_name": [{
        "toy": "car"
    }, {
        "tool": "knife"
    }]
}, {
    "section_name": "xyz",
    "id": 2,
    "new_property_name": [{
        "weapon": "cutter"
    }]
}]

Answer 1

ES6解決方案：

const arr = [{"section_name":"abc","id":1},{"section_name":"xyz","id":2}];
const arr2 = [{"toy":"car","id":1},{"tool":"knife","id":1},{"weapons":"cutter","id":2}];

const res = arr.map((section,index) => {
  section.new_property_name = arr2.filter(item => item.id === section.id);
  return section;
});

編輯：就像在評論中提到的georg一樣，上面的解決方案實際上是對arr變異，它修改了原始的arr （如果您在映射它之后登錄了arr，您將看到它已更改，對arr進行了變異並具有new_property_name ）。 它使.map()變得毫無用處，簡單的forEach()確實更合適並節省了一行。

arr.forEach(section => {
   section.new_property_name = arr2.filter(item => item.id === section.id));
});

Answer 2

嘗試這個

 var data1 = [{"section_name":"abc","id":1},{"section_name":"xyz","id":2}]; var data2 = [{"toy":"car","id":1},{"tool":"knife","id":1},{"weapons":"cutter","id":2}]; var map = {}; //first iterate data1 the create a map of all the objects by its ids data1.forEach( function( obj ){ map[ obj.id ] = obj }); //Iterate data2 and populate the new_property_name of all the ids data2.forEach( function(obj){ var id = obj.id; map[ id ].new_property_name = map[ id ].new_property_name || []; delete obj.id; map[ id ].new_property_name.push( obj ); }); //just get only the values from the map var output = Object.keys(map).map(function(key){ return map[ key ] }); console.log(output); 

Answer 3

您可以使用ah哈希表進行查找，並構建一個新對象以插入到new_property_name數組中。

 var array1 = [{ "section_name": "abc", "id": 1 }, { "section_name": "xyz", "id": 2 }], array2 = [{ "toy": "car", "section_id": 1 }, { "tool": "knife", "section_id": 1 }, { "weapons": "cutter", "section_id": 2 }], hash = Object.create(null); array1.forEach(function (a) { a.new_property_name = []; hash[a.id] = a; }); array2.forEach(function (a) { hash[a.section_id].new_property_name.push(Object.keys(a).reduce(function (r, k) { if (k !== 'section_id') { r[k] = a[k]; } return r; }, {})); }); console.log(array1); 

Answer 4

似乎通過使用Jquery $.merge()函數，您可以實現所需的功能。 然后，我們還有concat函數，可用於將一個數組與另一個數組合並。

Answer 5

使用Object.assign()

在您的情況下，您可以像Object.assign(array1[0], array2[0]) 。 合並對象非常好，因此，您只需要在數組中合並對象即可。

代碼示例：

var objA = [{"section_name":"abc","id":1},{"section_name":"xyz","id":2}];
var objB = [{"toy":"car","section_id":1},{"tool":"knife","section_id":1},{"weapons":"cutter","section_id":2}];
var objC = Object.assign({},objA[0],objB[0]);

console.log(JSON.stringify(objC));// {"section_name":"abc","id":1,"toy":"car","section_id":1}

有關更多信息，您可以在這里參考： Object.assign（）

Answer 6

 var firstArray = [{"section_name":"abc","id":1},{"section_name":"xyz","id":2}], secondArray = [{"toy":"car","section_id":1},{"tool":"knife","section_id":1},{"weapons":"cutter","section_id":2}]; var hash = Object.create(null); firstArray.forEach(s => { hash[s.id] = s; s['new_property_name'] = []; }); secondArray.forEach(i => hash[i['section_id']]['new_property_name'].push(i)); console.log(firstArray);