Javascript：将数组中的对象组改组 [英] Javascript: shuffling groups of objects in an array

问题描述

我有一个对象数组，其中已经对一个键（下面的组）进行了排序，因此所有对象的值都相同组在数据的索引中彼此相邻。例如：

I have an array of objects where I have sorted on a key (group below) such that all of the objects wit hthe same value for group are adjacent to each other in the indices of data. For example:

var data = [{foo: "cat", group:"house"},
            {foo: "cat", group: "house"},
            {foo: "cat", group: "tree"},
            {foo: "dog", group: "tree"},
            {foo: "dog", group: "car"}];

我正在尝试调整数据中对象的顺序数组，同时保留键 group 的值内的顺序。换句话说，我试图改组 data 中的对象组，而不是单个对象。虽然我知道如何随机排列数组中的对象，但我不知道如何随机排列数组中的对象组。

I am trying to shuffle the order of the objects in the data array while preserving the ordering within the values of the key group. In other words, I am trying to shuffle groups of objects in data and not the individual objects. While I know how to shuffle objects in an array, I don't know how to shuffle groups of object in an array.

我的想法是，可能有一种方法使用组的值仅在组更改时才更改的事实。

My thoughts were that there might be a way to use the fact that the values of group change only when the group changes.

推荐答案

只需创建一个随机属性即可在组级别，并将属性分配给数组中的每个对象：

Simply create a random property to sort with at the group level and assign the property to each respective object in the array:

var data = [{foo: "cat", group: "house"},
            {foo: "cat", group: "house"},
            {foo: "cat", group: "tree"},
            {foo: "dog", group: "tree"},
            {foo: "dog", group: "car"}];

//get random sorting at the group level (via a hashtable)
let randomGroupSortKey = {}
data.forEach(d => randomGroupSortKey[d.group] = Math.random())
console.log("Group sort keys:", randomGroupSortKey)

//add the sortKey property to the individual array entries
let dataSortable = data.map(x => {
  return {
    ...x, 
    sortKey: randomGroupSortKey[x.group]
  }
})

dataSortable.sort((a, b) => a.sortKey - b.sortKey) //sort the groups!

console.log("Result:", dataSortable)
console.log("Result without sortKey:", dataSortable.map(({ sortKey, ...x }) => x))

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