如何按属性对对象进行分组，同时对另一个对象求和

Question

我尝试了很多方法来解决这个问题。我可以删除重复值。但问题是更新 total_product 值。我怎样才能做到这一点？给我一些提示。

这是我的主阵列：

 const colors = [
    { "name": "Black", "total_product": 1 },
    { "name": "Black", "total_product": 1 },
    { "name": "White", "total_product": 1 },
    { "name": "White", "total_product": 1 },
    { "name": "White", "total_product": 1 },
    { "name": "White", "total_product": 1 },    
]

我想要这样的：

 const colors = [
    { "name": "Black", "total_product": 2 },
    { "name": "White", "total_product": 4 }         
]

Answer 1

您可以使用 new Map() 或简单对象来存储相同对象的计数：

const colors = [
  { "name": "Black", "total_product": 1 },
  { "name": "Black", "total_product": 1 },
  { "name": "White", "total_product": 1 },
  { "name": "White", "total_product": 1 },
  { "name": "White", "total_product": 1 },
  { "name": "White", "total_product": 1 },    
];

const colorsMap = new Map();

colors.forEach(color => {
  
  if (colorsMap.has(color.name)) {
    colorsMap.set(color.name, colorsMap.get(color.name) + 1);
    return;
  }
  
  colorsMap.set(color.name, 1);
});

const groupedColors = [];

colorsMap.forEach((value, key) => {
  groupedColors.push({
    name: key,
    total_product: value
  });
})

console.log(groupedColors);

Answer 2

reduce 是一个很好的例子，它将数组“归结”为累加器值。在这里，reduce (doc) 可用于创建计算每个名称出现次数的对象...

const colors = [
    { "name": "Black", "total_product": 1 },
    { "name": "Black", "total_product": 1 },
    { "name": "White", "total_product": 1 },
    { "name": "White", "total_product": 1 },
    { "name": "White", "total_product": 1 },
    { "name": "White", "total_product": 1 } 
];

const counts = colors.reduce((acc, obj) => {
  if (!acc[obj.name]) acc[obj.name] = { name: obj.name, total_product: 0 };
  acc[obj.name].total_product++;
  return acc;
}, {});
const result = Object.values(counts);
console.log(result);

reduce 产生的中间值 counts 看起来像这样...

{
  "Black": {
    "name": "Black",
    "total_product": 2 // <- incremented each time we found a "Black"
  },
  "White": {
    "name": "White",
    "total_product": 4 // <- incremented each time we found a "White"
  }
}

Object.values()，顾名思义，生成一个值数组。

Answer 3

const colors = [
  { name: "Black", total_product: 1 },
  { name: "Black", total_product: 1 },
  { name: "White", total_product: 1 },
  { name: "White", total_product: 1 },
  { name: "White", total_product: 1 },
  { name: "White", total_product: 1 }
];

const uniqueColors = (colors) => {
  const unique = [];
  colors.map((color) => {
    const index = unique.findIndex((c) => c.name === color.name);
    if (index === -1) {
      unique.push(color);
    } else {
      unique[index].total_product++;
    }
  });
  return unique;
};

console.log(uniqueColors(colors));

Answer 4

return 数组没有任何意义，因为您已经 将数组压缩 为唯一的名称及其各自的值，只需简化为对象：

const colors = [
  {name:"Black", total_product:1},
  {name:"Black", total_product:1},
  {name:"White", total_product:1},
  {name:"White", total_product:1},
  {name:"White", total_product:1},
  {name:"White", total_product:1},    
];

const sumColors = colors.reduce((ob, item) => {
  ob[item.name] ??= 0
  ob[item.name] += item.total_product;
  return ob;
}, {});

console.log(sumColors); // {"Black": 2, "White": 4}

如何按属性对对象进行分组，同时对另一个对象求和

How to group objects by some property while summing another

javascript

arrays

object

这是我的主阵列：

我想要这样的：

如何按 属性 对对象进行分组，同时对另一个对象求和

How to group objects by some property while summing another

javascript

arrays

object

这是我的主阵列：

我想要这样的：

如何按属性对对象进行分组，同时对另一个对象求和