Question

试图求和数组中对象的值

我有3个对象，每个对象中都有两个字段，其中我声明了值：

let items = [
       {
        id: 1, 
        label: 'test', 
        itemname: 'testitem', 
        pieces: 4,
        weight: 0.02
      },
      {
        id: 2, 
        label: 'test', 
        itemname: 'testitem', 
        pieces: 4,
        weight: 0.02
      },
      {
        id: 2, 
        label: 'test', 
        itemname: 'testitem', 
        pieces: 4,
        weight: 0.02
      }
    ];

因此，如果我是对的，则权重之和将为0.06，而总和为12，两者相乘即为0.72，这意味着我想将权重之和与总和相乘。 / p>

我看到了这样的例子：

const weight = items.reduce((prev, cur) => {
  return prev + (cur.weight * cur.pieces);
}, 0);
console.log(weight);

在此示例中，总和仅为0.24。有人可以帮我吗

编辑：@Robby Cornelissen的评论正确。我这是一种错误的思维方式。

Answer 1

如果要获得所有物品的总重量，则必须先获取每个物品的重量，然后将它们加在一起。

const sum = (arr) => {
    return arr.map(item => item.pieces * item.weight).reduce((current, total) => current + total)
}

let items = [{
    id: 1,
    label: 'test',
    itemname: 'testitem',
    pieces: 4,
    weight: 0.02
  },
  {
    id: 2,
    label: 'test',
    itemname: 'testitem',
    pieces: 4,
    weight: 0.02
  },
  {
    id: 2,
    label: 'test',
    itemname: 'testitem',
    pieces: 4,
    weight: 0.02
  }
]

const sum = (arr) => {
  return arr.map(item => item.pieces * item.weight).reduce((current, total) => current + total)
}

const totalWeight = sum(items)

console.log(totalWeight)

Answer 2

您可以使用import warnings warnings.filterwarnings("ignore", category=UserWarning, module="torch.nn.functional")遍历数组，将forEach和pieces的值相加：

weight

然后乘以let pieces = 0; // sum of pieces let weight = 0; // sum of weight items.forEach(function(elmt){ pieces += elmt.pieces; weight += elmt.weight; }); * pieces：

weight

Answer 3

使用class

let items=[{id:1,label:"test",itemname:"testitem",pieces:4,weight:.02},{id:2,label:"test",itemname:"testitem",pieces:4,weight:.02},{id:2,label:"test",itemname:"testitem",pieces:4,weight:.02}];

class total {
  weight = 0;
  pieces = 0;
  get product() {
    return this.weight * this.pieces;
  }
}

const totalObj = items.reduce((prev, cur) => {
  prev.weight += cur.weight;
  prev.pieces += cur.pieces;
  return prev;
}, new total);

console.log(totalObj.product);

数组中对象的总和

3 个答案: