Question

我正在尝试迭代具有相似键值的对象数组，并且想要计算它们的值在整个对象数组中重复的次数，例如在整个对象中计算“晚餐”

var objects = [
  { Ram: 'Lunch',  Luv:'Lunch',  Rani:'Dinner' },
  { Ram: 'Dinner', Luv:'Lunch',  Rani:'Dinner' },
  { Ram: 'Lunch',  Luv:'Dinner', Rani:'Dinner' }
];

我正在尝试计算午餐发生了多少次以及晚餐发生了多少次，并希望在这样的json下面显示 -

[{'Dinner':5}, {'Lunch':4}];

我如何在javascript中实现这一目标？

Answer 1

您可以将reduce()与Object.values()一起使用，并返回一个对象而不是对象数组。

var objects=[
{Ram:'Lunch', Luv:'Lunch', Rani:'Dinner'},
{Ram:'Dinner', Luv:'Lunch', Rani:'Dinner'},
{Ram:'Lunch', Luv:'Dinner', Rani:'Dinner'}
]

const result = objects.reduce((r, o) => {
  Object.values(o).forEach(e => r[e] = (r[e] || 0) + 1)
  return r;
}, {});

console.log(result)

Answer 2

因为我不喜欢forEach，所以这里是 double-reduce ：

const objects = [
  { Ram: 'Lunch',  Luv: 'Lunch',  Rani: 'Dinner' },
  { Ram: 'Dinner', Luv: 'Lunch',  Rani: 'Dinner' },
  { Ram: 'Lunch',  Luv: 'Dinner', Rani: 'Dinner' }
];

const count = objects
  // collect and flatten object values
  .reduce((a, o) => a.concat(Object.values(o)), [])

  // count individual
  .reduce((c, v) => ({...c, [v]: (c[v] || 0) + 1}), {})
;

const list = Object.entries(count)
  // map to {type, count}
  .map(([type, count]) => ({type, count}))
;

console.log(count, list);

Answer 3

将reduce与forEach

一起使用

var output = objects.reduce( (a, c) => 
    (Object.values(c).forEach( 
       s => a[s] = (a[s] || 0) + 1 ), //end forEach
    a), 
{})//end reduce

<强>演示

var objects = [{
    Ram: "Lunch",
    Luv: "Lunch",
    Rani: "Dinner"
  },
  {
    Ram: "Dinner",
    Luv: "Lunch",
    Rani: "Dinner"
  },
  {
    Ram: "Lunch",
    Luv: "Dinner",
    Rani: "Dinner"
  }
];
var output = objects.reduce((a, c) => (Object.values(c).forEach(s => a[s] = (a[s] || 0) + 1), a), {});
console.log(output);

计算对象数组中键的值的重复计数

3 个答案: