Sort a map by its values

valsort.go

package main

import "fmt"
import "sort"

func main() {
        m := map[string]int{
                "One":   1,
                "Two":   2,
                "Three": 3,
                "Ten":   10,
                "Fifty": 50,
        }
        vs := NewValSorter(m)
        fmt.Printf("%v\n", *vs)
        vs.Sort()
        fmt.Printf("%v\n", *vs)
}

type ValSorter struct {
        Keys []string
        Vals []int
}

func NewValSorter(m map[string]int) *ValSorter {
        vs := &ValSorter{
                Keys: make([]string, 0, len(m)),
                Vals: make([]int, 0, len(m)),
        }
        for k, v := range m {
                vs.Keys = append(vs.Keys, k)
                vs.Vals = append(vs.Vals, v)
        }
        return vs
}

func (vs *ValSorter) Sort() {
        sort.Sort(vs)
}

func (vs *ValSorter) Len() int           { return len(vs.Vals) }
func (vs *ValSorter) Less(i, j int) bool { return vs.Vals[i] < vs.Vals[j] }
func (vs *ValSorter) Swap(i, j int) {
        vs.Vals[i], vs.Vals[j] = vs.Vals[j], vs.Vals[i]
        vs.Keys[i], vs.Keys[j] = vs.Keys[j], vs.Keys[i]
}

xoutput

{[Ten Fifty One Three Two] [10 50 1 3 2]}
{[One Two Three Ten Fifty] [1 2 3 10 50]}