在对象数组中，如何根据对象属性进行聚合? [英] In an array of objects, how can I aggregate based on object property?

问题描述

假设我有以下对象数组:

Say I have the following array of objects:

dataArray = [ 
  { id: "a", score: 1 }, 
  { id: "b", score: 2 }, 
  { id: "c", score: 5 }, 
  ...
  { id: "a", score: 3 },
  ...
  { id: "c", score: 2},
  ...
 ]

如何获得如下的 resultArray:

How can I obtain a resultArray like the following:

resultArray = [
  { id: "a", score: sum of all the scores when id is a },
  { id: "b", score: sum of all the scores when id is b },
  ...
  ...
]

推荐答案

如果使用下划线库:

_.map  _.groupBy(dataArray, 'id'), (v, k) -> 
    {id: k, score: _.reduce(v, ((m, i) -> m + i['score']), 0) }

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