对Javascript对象中的两个值求和

Question

如果我有一个像这样的javascript对象：

sampleObject[
   {
    suite: "Clubs",
    weight : 10
   },
   {
    suite: "Spades",
    weight : 6
   },
   {
    suite: "Hearts",
    weight : 2
   }
];

我该如何找到重量属性的总和？

Answer 1

简单的总和减少应该起作用。

var sum = sampleObject.reduce(( sum, card ) => sum + card.weight, 0 );

Answer 2

您可以map您的对象，然后reduce它：

1. samplObject => [weight0, weight1, weight2]
2. [weight0, weight1, weight2] => weight0 + weight1 + weight2

这意味着您将初始列表转换为权重列表，然后将值一一求和。

const sampleObject = [
  {
    suite: "Clubs",
    weight : 10
  },
  {
    suite: "Spades",
    weight : 6
  },
  {
    suite: "Hearts",
    weight : 2
  }
];

let sum = sampleObject.map( el=> el.weight).reduce( (a,b) => a+b);
console.log(sum)

输出：

18

注意：

在此特定示例中，map是开销。您可以轻松地计算总和：

let sum = sampleObject.reduce( (a,b) => a+b.weight,0);

但是对于更复杂的数据结构，总的来说，牢记map-reduce的概念是很好的。

Answer 3

使用reduce方法并将初始值作为0传递。您还可以使用normal for循环或forEach方法

let sampleObject = [{
    suite: "Clubs",
    weight: 10
  },
  {
    suite: "Spades",
    weight: 6
  },
  {
    suite: "Hearts",
    weight: 2
  }
];

let sum = sampleObject.reduce(function(acc, curr) {
  //Initially the value of acc will be 0
 // curr is the current object in context
  acc += curr.weight
   return acc;
}, 0)
console.log(sum)

Answer 4

使用Array.reduce

sampleObject = [
   {
    suite: "Clubs",
    weight : 10
   },
   {
    suite: "Spades",
    weight : 6
   },
   {
    suite: "Hearts",
    weight : 2
   }
];

var sum = sampleObject.reduce((a, b) => a + b.weight, 0);

console.log(sum);

Answer 5

由于具有对象数组，因此可以执行以下操作来访问第一个“ weight”变量：sampleObject[0].weight。考虑到这一点，您可以使用一个简单的for循环将它们加在一起：

var sum = 0

for(var i = 0; i < sampleObject.length; i+){
  sum += sampleObject[i].weight
} 
console.log(sum)

Answer 6

使用reduce：

let sampleObject = [{
  suite: "Clubs",
  weight : 10
}, {
  suite: "Spades",
  weight : 6
}, {
  suite: "Hearts",
  weight : 2
}];

let sum = sampleObject.reduce((a, b) => a + b.weight, 0);
console.log(sum);