Question

我有一个对象数组，其中包含一个poll的结果，它看起来（例如）像这样：

[
    {title: 'cat', optionid: 7, points: 1 }, 
    {title: 'cat', optionid: 7, points: 3 }, 
    {title: 'cat', optionid: 7, points: 1 }, 
    {title: 'dog', optionid: 8, points: 3 }, 
    {title: 'dog', optionid: 8, points: 2 }, 
    {title: 'dog', optionid: 8, points: 3 }, 
    {title: 'pig', optionid: 9, points: 2 }, 
    {title: 'pig', optionid: 9, points: 1 }, 
    {title: 'pig', optionid: 9, points: 1 }
]

基本上，我想循环并总结每个optionid / title的点。所以cat = 5，dog = 8，pig = 4.有没有办法在JavaScript中执行此操作？到目前为止我的所有尝试都失败了。我是自学成才的，只是一个初学者，所以解决方案越不复杂就越好。

Answer 1

使用reduce

非常容易

var arr = [{title: 'cat', optionid: 7, points: 1 },
{title: 'cat', optionid: 7, points: 3 },
{title: 'cat', optionid: 7, points: 1 },
{title: 'dog', optionid: 8, points: 3 },
{title: 'dog', optionid: 8, points: 2 },
{title: 'dog', optionid: 8, points: 3 },
{title: 'pig', optionid: 9, points: 2 },
{title: 'pig', optionid: 9, points: 1 },
{title: 'pig', optionid: 9, points: 1 }]
var result = arr.reduce(function(acc, v) {
  acc[v.title] = (acc[v.title] || 0) + v.points
  return acc
}, {})
console.log(result)

Answer 2

使用reduce

   div { height: 0px; 
         opacity: 0; 
         transition: opacity 0.5s; }

  .active { height: 100%;
            opacity: 1;
            transition: opacity 0.5s; }

Answer 3

我认为使用reduce是最好的方式。然而，像我这样的新手可能会让人感到困惑。所以这是一个更直接的方法。希望这更容易理解。

＆＃13;

var animals = [{title: 'cat', optionid: 7, points: 1 },
{title: 'cat', optionid: 7, points: 3 },
{title: 'cat', optionid: 7, points: 1 },
{title: 'dog', optionid: 8, points: 3 },
{title: 'dog', optionid: 8, points: 2 },
{title: 'dog', optionid: 8, points: 3 },
{title: 'pig', optionid: 9, points: 2 },
{title: 'pig', optionid: 9, points: 1 },
{title: 'pig', optionid: 9, points: 1 }];

// create new object to store results in
newObj = {};

// loop through animal objects
animals.forEach(function(animal){
 // check if animal type has already been added to newObj
 if(!newObj[animal.title]){
  // If it is the first time seeing this animal type
  // we need to add title and points to prevent errors
  newObj[animal.title] = {};
  newObj[animal.title]['points'] = 0;
 }
 // add animal points to newObj for that animal type.
 newObj[animal.title]['points'] += animal.points 
})
console.log(newObj)

＆＃13;

循环遍历对象数组并返回某些值的总和

3 个答案: