Javascript 如何对对象数组进行分组和求和？

how to group by and sum array of object?

提问by Phirum

I would like to Group Object of Array by Id and sum by quantity in Jquery? For example:

我想在 Jquery 中按 Id 对数组对象进行分组并按数量求和？例如：

var array = [
  { Id: "001", qty: 1 },
  { Id: "002", qty: 2 },
  { Id: "001", qty: 2 },
  { Id: "003", qty: 4 }
]

After I Group it by the Id I will get the new Array like:

在我按 Id 对它进行分组后，我将得到新的数组，如：

 [
    { Id: "001", qty: 3 },
    { Id: "002", qty: 2 },
    { Id: "003", qty: 4 }
 ]

回答by Arun P Johny

You can loop and sum it up

你可以循环并总结

var array = [
  { Id: "001", qty: 1 }, 
  { Id: "002", qty: 2 }, 
  { Id: "001", qty: 2 }, 
  { Id: "003", qty: 4 }
];

var result = [];
array.reduce(function(res, value) {
  if (!res[value.Id]) {
    res[value.Id] = { Id: value.Id, qty: 0 };
    result.push(res[value.Id])
  }
  res[value.Id].qty += value.qty;
  return res;
}, {});

console.log(result)

Fiddle: Fiddle

小提琴：小提琴

回答by Sadikhasan

var newArr = [];

$.each(array,function(index,element){
    if(newArr[element.Id]==undefined){
        newArr[element.Id] =0;
    }
    newArr[element.Id] += element.qty;
});
console.log(newArr);

Demo

演示