使用与值GO匹配的键对地图数组进行排序

Question

我刚刚开始在Golang中编程，想对地图数组进行排序。我有一系列的地图。我们称之为example_array。

example_array = [
  [
    { Name: "A", Value: 100 }, 
    { Name: "B", Value: 60 }, 
    { Name: "C", Value: 170 }, 
    { Name: "D", Value: 120} 
  ], 
  [
    { Name: "A", Value: 64 }, 
    { Name: "B", Value: 90 }, 
    { Name: "C", Value: 52 }, 
    { Name: "D", Value: 98} 
  ], 
  [
    { Name: "A", Value: 154 }, 
    { Name: "B", Value: 190 }, 
    { Name: "C", Value: 179 }, 
    { Name: "D", Value: 67 } 
  ]

]

现在我想使用key的值对该数组进行排序，"C"因此example_array应该修改为->

[
[{Name: "A", Value: 64}, {Name: "B", Value: 90}, {Name: "C", Value: 52}, {Name: "D", Value: 98}],
[{Name: "A", Value: 100}, {Name: "B", Value: 60}, {Name: "C", Value: 170}, {Name: "D", Value: 120}], 
[{Name: "A", Value: 154}, {Name: "B", Value: 190}, {Name: "C", Value: 179}, {Name: "D", Value: 67}]
]

如果我使用key的值对原始数组进行排序"D"，则应将原始数组修改为->

[
[{Name: "A", Value: 154}, {Name: "B", Value: 190}, {Name: "C", Value: 179}, {Name: "D", Value: 67}],
[{Name: "A", Value: 64}, {Name: "B", Value: 90}, {Name: "C", Value: 52}, {Name: "D", Value: 98}]
[{Name: "A", Value: 100}, {Name: "B", Value: 60}, {Name: "C", Value: 170}, {Name: "D", Value: 120}]
]

如何在Golang中对这些地图数组进行排序。请帮忙！

Answer 1

您的数据看起来很容易表示为type of map的一部分map[string]int。由于您没有在问题中提供任何Go代码，因此我不确定数据类型，因此我将假定它是map[string]int此答案中类型的映射的一部分。

A simple way to sort a slice of maps is to use the sort.Slice function. From a comment in the first example in the sort package documentation:

use sort.Slice with a custom Less function, which can be provided as a closure. In this case no methods are needed

The Less function needs to satisfy the signature

func(i, j int) bool

Per package documentation (at Interface):

Less reports whether the element with index i should sort before the element with index j.

Using a closure allows you to reference your data structure in the function body even though it is not part of the parameter list.

Here's a runnable example that sorts a slice of map[string]int values matching the data in your question:

package main

import(
    "fmt"
    "sort"
)

func main() {
    in := []map[string]int{
        {
          "A": 100,
          "B": 60,
          "C": 170,
          "D": 120,
        },
        {
          "A": 64,
          "B": 90,
          "C": 52,
          "D": 98,
        },
        {
          "A": 154,
          "B": 190,
          "C": 179,
          "D": 67,
        },
    }
    for k, _ := range in[0] {
        sort.Slice(in, func(i, j int) bool { return in[i][k] < in[j][k] })
        fmt.Printf("By %s: %v\n", k, in)
    }
}

Output:

By A: [map[A:64 B:90 C:52 D:98] map[A:100 B:60 C:170 D:120] map[A:154 B:190 C:179 D:67]]
By B: [map[A:100 B:60 C:170 D:120] map[B:90 C:52 D:98 A:64] map[C:179 D:67 A:154 B:190]]
By C: [map[A:64 B:90 C:52 D:98] map[A:100 B:60 C:170 D:120] map[A:154 B:190 C:179 D:67]]
By D: [map[A:154 B:190 C:179 D:67] map[B:90 C:52 D:98 A:64] map[A:100 B:60 C:170 D:120]]