如何循环包含Javascript中的对象的对象

Question

我有一个看起来像这样的对象（我们称其为帖子）

[ { _id: 5cc2d552939a9b290bfaee18,

    rating: 1,

    __v: 0 },

  { _id: 5cc2d6362c9b3729253d14eb,

    rating: 4,

    __v: 0 } ]

该对象的大小改变。

每次调用该函数时，我都希望遍历帖子，并求和。然后，我想将等级除以帖子中的项目数。

我试图做这样的事情

Object.keys(posts).forEach(function (item, value) {

        });

但是无法获取实际数据

Answer 1

我有一个对象（我们称它为post）。我们称其为array或map。而且，您始终可以遍历数组。您可以for为此使用简单循环。循环将使您获得数组元素一个接一个的元素，在您的情况下这将是对象。现在，您可以轻松获取rating每个对象的属性值并将它们加起来，然后除以数组的长度。你应该以类似var data = [ { _id: '5cc2d552939a9b290bfaee18',&nbsp; &nbsp; &nbsp; &nbsp; rating: 1,&nbsp; &nbsp; &nbsp; &nbsp; __v: 0 },&nbsp; &nbsp; &nbsp; { _id: '5cc2d6362c9b3729253d14eb',&nbsp; &nbsp; &nbsp; &nbsp; rating: 4,&nbsp; &nbsp; &nbsp; &nbsp; __v: 0 } ];&nbsp; &nbsp; var sum = 0;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp; for(var i=0; i< data.length; i++){&nbsp; &nbsp; &nbsp; sum = sum + data[i].rating;&nbsp; &nbsp; }&nbsp; &nbsp; var result = sum/data.length;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp; console.log(result);我已经解释了这一切，所以您不仅可以复制并粘贴它。请务必阅读说明。

Answer 2

你有一个数组，而不是一个对象。您需要遍历数组，而不是对象&nbsp;let posts = [&nbsp;{ _id: 5cc2d552939a9b290bfaee18,rating: 1, __v: 0 },{ _id: 5cc2d6362c9b3729253d14eb,rating: 4,__v: 0 }&nbsp;], sum = 0, average = 0;//so you need the average of the ratings, get the sum of the ratingsposts.map(post => sum += post.rating);//divide the sum by the length of the itemsaverage = sum/posts.length

Answer 3

哦，对于初学者来说，您遍历仅键的数组就Object.keys可以得到键，而不是值，这样就没用了。&nbsp; &nbsp; function getAverageRating(posts, detailed)&nbsp; &nbsp; {&nbsp; &nbsp; &nbsp; &nbsp; let totalPosts = 0;&nbsp; &nbsp; &nbsp; &nbsp; let totalRatings = 0;&nbsp; &nbsp; &nbsp; &nbsp; posts.forEach(function (item, index) {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; totalRatings += item.rating;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; totalPosts++;&nbsp; &nbsp; &nbsp; &nbsp; });&nbsp; &nbsp; &nbsp; &nbsp; if(detailed){&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; return {"total_posts":totalPosts, "sum_ratings":totaltotalRatings, "avg":totaltotalRatings/totalPosts}&nbsp; &nbsp; &nbsp; &nbsp; }else{&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; return totaltotalRatings/totalPosts&nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; }