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基于2个键的属性减少数组

object arrays javascript

arunmmanoharan · 技术社区 · 6 年前

我有一个这样的数组。

var data = [{
  name: 'Apple',
  category: 'Fruit',
  value: 12
}, {
  name: 'Apple',
  category: 'Fruit',
  value: 20
}, {
  name: 'Orange',
  category: 'Fruit',
  value: 65
}, {
  name: 'Orange',
  category: 'Fruit',
  value: 40
}]

我需要一个这样的数组:

var newData = [{
  name: 'Apple',
  category: 'Fruit',
  value: 20
}, {
  name: 'Orange',
  category: 'Fruit',
  value: 65
}]

即获取数组中每个“name”键的最大值。

var data = [{
  name: 'Apple',
  category: 'Fruit',
  value: 12
}, {
  name: 'Apple',
  category: 'Fruit',
  value: 20
}, {
  name: 'Orange',
  category: 'Fruit',
  value: 65
}, {
  name: 'Orange',
  category: 'Fruit',
  value: 40
}]

console.log(data.reduce(function(prev, current) {
  return (prev.name !== current.name && prev.value > current.value) ? prev : current
}))

请给我建议。

4 回复 | 直到 6 年前

CertainPerformance 6 年前

你需要跟踪当前的最高点 value 每一个 name 名称 价值

var data = [{
  name: 'Apple',
  category: 'Fruit',
  value: 12
}, {
  name: 'Apple',
  category: 'Fruit',
  value: 20
}, {
  name: 'Orange',
  category: 'Fruit',
  value: 65
}, {
  name: 'Orange',
  category: 'Fruit',
  value: 40
}];

console.log(Object.values(
  data.reduce((a, item) => {
    const { name, value } = item;
    if (!a[name] || a[name].value < value) a[name] = item;
    return a;
  }, {})
));

(您的 prev.name !== current.name ... 只有当你只想因为你需要更多,所以你需要一个可以包含多个项目的对象。)

brk 6 年前

使用reduce并检查累加器阵列是否与使用reduce的结果相同 findIndex

var data = [{
  name: 'Apple',
  category: 'Fruit',
  value: 12
}, {
  name: 'Apple',
  category: 'Fruit',
  value: 20
}, {
  name: 'Orange',
  category: 'Fruit',
  value: 65
}, {
  name: 'Orange',
  category: 'Fruit',
  value: 40
}]



let result = data.reduce(function(acc, curr) {

  let findIfExist = acc.findIndex(elem => {
    return elem.name === curr.name;
  })
  if (findIfExist === -1) {
    acc.push(curr)
  } else {
    if (acc[findIfExist].value < curr.value) {
      acc[findIfExist].value = curr.value
    }

  }

  return acc;

}, [])

console.log(result)

Ramesh César Landesa 6 年前

使用 forEach reduce

var data = [{
  name: 'Apple',
  category: 'Fruit',
  value: 12
}, {
  name: 'Apple',
  category: 'Fruit',
  value: 20
}, {
  name: 'Orange',
  category: 'Fruit',
  value: 65
}, {
  name: 'Orange',
  category: 'Fruit',
  value: 40
}]

let result = {};
data.forEach(function(current) {
  if (result[current.name] &&
    result[current.name].value < current.value &&
    result[current.name].category === current.category) {
    result[current.name].value = current.value;
  } else if (!result[current.name]) {
    result[current.name] = current;
  }
});
console.log(Object.values(result));

Monica Acha 6 年前

var data = [{
  name: 'Apple',
  category: 'Fruit',
  value: 12
}, {
  name: 'Apple',
  category: 'Fruit',
  value: 20
}, {
  name: 'Orange',
  category: 'Fruit',
  value: 65
}, {
  name: 'Orange',
  category: 'Fruit',
  value: 40
}]
let result=data.reduce(function(temp, current) {
  //check if temp has object
  var found = temp.some((el) => {
      return el.name === current.name
    });
  //if not found, add the object
    if (!found) { temp.push(current) }
  //if found and value is greater, replace the max value
  else{
    temp.find((element) => {
     if(element.name === current.name && element.value<current.value)
    element.value=current.value
    })
  }
  return temp
},[])
console.log(result);