Question

下面是从我的json响应中生成的数组

 [
        {
    "id": "name1",
    "c1": "10",
    "c2": "20",
    "c3": "30",
    "c4": "40"
        },
    {
    "id": "name2",
    "c1": "20",
    "c2": "40",
    "c3": "25",
    "c4": "38"
        }
    ]

我需要计算除第一个字段以外的字段值的总和，因为我得到的第一个是字段名称

结果数组：

  [
    "c1": 30,
    "c2": 60,
    "c3": 55,
    "c4": 78
      ]

Answer 1

仅使用ES6，您可以使用2个Array#reduce循环执行此操作：

＆＃13;

const data = [{"id":"name1","c1":"10","c2":"20","c3":"30","c4":"40"},{"id":"name2","c1":"20","c2":"40","c3":"25","c4":"38"}];

const result = data.reduce((sums, obj) => Object.keys(obj).reduce((s, k) => {    
    k === 'id' || (s[k] = (s[k] || 0) + +obj[k]);
    
    return s;
}, sums), {});

console.log(result);

＆＃13;

或者您可以使用lodash＆＃39; _.mergeWith()和_.omit()＆＃39; id＆＃39;从结果：

＆＃13;

const data = [{"id":"name1","c1":"10","c2":"20","c3":"30","c4":"40"},{"id":"name2","c1":"20","c2":"40","c3":"25","c4":"38"}];

const result = _.omit(_.mergeWith({}, ...data, (objValue = 0, srcValue = 0) => +objValue + +srcValue), 'id');

console.log(result);

 console.log(_.map(result, (v, k) => ({ [k]: v }))); // or as a series of objects

＆＃13;

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.4/lodash.min.js"></script>

＆＃13;

Answer 2

ES6语法：

＆＃13;

const a =  [
        {
    "id": "name1",
    "c1": "10",
    "c2": "20",
    "c3": "30",
    "c4": "40"
        },
    {
    "id": "name2",
    "c1": "20",
    "c2": "40",
    "c3": "25",
    "c4": "38"
        }
    ];

const b = a.reduce((a, v) => {
  Object.keys(v).filter(e => e.startsWith('c')).forEach(k => a[k] = (a[k]) ? a[k] + +v[k] : +v[k]);
  return a;  
}, {});
   
console.log(b)

＆＃13;

Answer 3

var values = [{
        "id": "name1",
        "c1": "10",
        "c2": "20",
        "c3": "30",
        "c4": "40"
    },
    {
        "id": "name2",
        "c1": "20",
        "c2": "40",
        "c3": "25",
        "c4": "38"
    }
];

var results = {
    "id": "totals",
    "c1": 0,
    "c2": 0,
    "c3": 0,
    "c4": 0
}

values.forEach(function(item) {
    results.c1 += Number(item.c1);
    results.c2 += Number(item.c2);
    results.c3 += Number(item.c3);
    results.c4 += Number(item.c4);
});

console.log(JSON.stringify(results));

Answer 4

假设您正在寻找一个结果对象，而不是一个对象数组：

var srcObj = [{
    "id": "name1",
    "c1": "10",
    "c2": "20",
    "c3": "30",
    "c4": "40"
  },
  {
    "id": "name2",
    "c1": "20",
    "c2": "40",
    "c3": "25",
    "c4": "38"
  }
];

var destObj = {};
srcObj.map((itm) => {
  Object.keys(itm).forEach(function (key) {
    if(key == 'id'){return;}
    if(!destObj[key]){
      destObj[key] = 0;
    }
    destObj[key] += parseInt(itm[key]);
  });
});

console.log(destObj);

Answer 5

使用lodash尝试

和

_.sum([4, 2, 8, 6]);
// => 20

sumby

var objects = [{ 'n': 4 }, { 'n': 2 }, { 'n': 8 }, { 'n': 6 }];

_.sumBy(objects, function(o) { return o.n; });
// => 20

// The `_.property` iteratee shorthand.
_.sumBy(objects, 'n');
// => 20

json数组的值之和

5 个答案: