Question

我需要计算亚马逊网站上的五星评级。我已经做了足够的搜索来找到最好的算法，但我无法得到正确的答案。例如，如果这些是评级

5 star - 252
4 star - 124
3 star - 40
2 star - 29
1 star - 33

共478条评论

亚马逊已将此计算为“4.1星满分5星”。谁能告诉我这个数字是如何得出的？我只能做平均值才能得到这个。

Answer 1

这是一个加权平均值，您可以根据得票数来衡量每个评级：

(5*252 + 4*124 + 3*40 + 2*29 + 1*33) / (252+124+40+29+33) = 4.11 and change

Answer 2

在evanmiller.org上有一篇关于这个主题的文章。他介绍并讨论了一些方法的优缺点，并提出了一种数学上可靠的加权和计算投票方式。

http://evanmiller.org/ranking-items-with-star-ratings.html

Answer 3

如果您从头开始计算总体评分，那么此公式将对您有所帮助。

式

((Overall Rating * Total Rating) + new Rating) / (Total Rating + 1)

实施例

假设你到目前为止没有评级那么公式就像，到目前为止整体评价为“0”。总评分“0” 并给出评级为“4”

((0*0)+4)/1 = 4

如果总体评级是“4.11”总评分是“478”并且新评分由一个用户给出的是“2”

然后公式就像

((4.11 * 478)+ 2)/479 // 479 is increment of new rating from 478

Answer 4

是的，你可以将它们平均化：

（5 * 252 + 4 * 124 + 3 * 40 + 2 * 29 + 1 * 33）/ 478 = 4.11

Answer 5

此评分系统基于weighted average或加权平均值。也就是说，他们使用星星的权重来计算舍入到4.1的十进制值。例如：

Sum of (weight * number of reviews at that weight) / total number of reviews
(5*252 + 4*124 + 3*40 + 2*29 + 1*33) / 478 = 4.1

Answer 6

Blindy的超级有用的回复，这里是基于它的PHP代码。有些人可能觉得有用。根据OP的例子，结果将是4.11：

$ratings = array(
5 => 252,
4 => 124,
3 => 40,
2 => 29,
1 => 33
);

function calcAverageRating($ratings) {

$totalWeight = 0;
$totalReviews = 0;

foreach ($ratings as $weight => $numberofReviews) {
    $WeightMultipliedByNumber = $weight * $numberofReviews;
    $totalWeight += $WeightMultipliedByNumber;
    $totalReviews += $numberofReviews;
}

//divide the total weight by total number of reviews
$averageRating = $totalWeight / $totalReviews;

return $averageRating;
}

Answer 7

你可能想要检查这个算法：Calculating Average Rating the Right Way using PHP and MySQL - 不需要保存每个“星”（也就是评级等级）及其相应的投票数，然后每个必须从数据库中检索数千行你需要计算他们的平均时间。（除非您想准确显示有多少人将给定项目评为1,2,3,4和5星）

Answer 8

加权平均值，将星数乘以其权重，然后除以总评论数。

Answer 9

根据您的问题，您的解决方案将是这样。

（Rate * TotalRatingOfThatRate）/ TotalNumberOfReviews之和

（（（5 * 252）+（4 * 124）+（3 * 40）+（2 * 29）+（1 * 33））/（252 + 124 + 40 + 29 + 33）

输出将为4.1

Answer 10

一种更好的方法，

rating = (sum_of_rating * 5)/sum_of_max_rating_of_user_count

示例：

total users rated: 6  
sum_of_max_rating_of_user_count: 6 x 5 = 30  
sum_of_rating: 25

rating = (25 * 5) / 30

完成！

Answer 11

使用Javascript

sudo chown -R hadoop:hadoop hadoop-3.2.0/

$ hadoop version

Hadoop 3.2.0
Source code repository https://github.com/apache/hadoop.git -r e97acb3bd8f3befd27418996fa5d4b50bf2e17bf

Compiled by sunilg on 2019-01-08T06:08Z

Compiled with protoc 2.5.0

From source with checksum d3f0795ed0d9dc378e2c785d3668f39
This command was run using /opt/hadoop-3.2.0/share/hadoop/common/hadoop-common-3.2.0.jar

Answer 12

（星级总数/评论总数* 5）* 5

=答案

将js中的小数固定为1。

answer.toFixed（1）;

例如5人的总评价为20星。

（20/5 * 5）* 5 = 4.0

Answer 13

此外，我只是想为所有人编写实用而完整的代码。

我的Json对象数组

var yourRatingData =[{
        review_id:1,
        customer_id:5,
        customer_name:"Faysal",
        rating:5,
        review_content:"I like this product it's cool and best in quality"
    },
    {
        review_id:2,
        customer_id:6,
        customer_name:"Adams",
        rating:4,
        review_content:"It's quality product though price a bit high"
    },
    {
        review_id:3,
        customer_id:8,
        customer_name:"Jane",
        rating:3,
        review_content:"I like but should improve quality"
    },
    {
        review_id:4,
        customer_id:9,
        customer_name:"Julia",
        rating:1,
        review_content:"It's not good"
    }];

评分计算

let _5star = yourRatingData.filter(r=>r.rating==5).length;
let _4star = yourRatingData.filter(r=>r.rating==4).length;
let _3star = yourRatingData.filter(r=>r.rating==3).length;
let _2star = yourRatingData.filter(r=>r.rating==2).length;
let _1star = yourRatingData.filter(r=>r.rating==1).length;

//Sum of individual star.
let sumOfRating = parseInt( _5star + _4star + _3star + _2star + _1star );

//Total number of rating
let overallRating = parseInt( 5*_5star + 4*_4star + 3*_3star + 2*_2star +1*_1star );

//Average of all rating
let averageRating = parseFloat(overallRating/sumOfRating);

//Percentage of each star rating
let _5starPercentage = parseInt((_5star/totalRating)*100);
let _4starPercentage = parseInt((_4star/totalRating)*100);
let _3starPercentage = parseInt((_3star/totalRating)*100);
let _2starPercentage = parseInt((_2star/totalRating)*100);
let _1starPercentage = parseInt((_1star/totalRating)*100);

我认为这很有帮助。

Answer 14

使用C＃

double rating = (double)(5 * star5 + 4 * star4 + 3 * star3 + 2 * star2 + 1 * star1) / (star1 + star2 + star3 + star4 + star5);
rating = Math.Round(rating, 1);

用于计算5星评级的算法

14 个答案: