Traverse a Map in decreasing order of values

Question

I'm trying to traverse a map in decreasing order of the values stored against keys. I've tried:

func frequencySort(s string) string {
  var frequency map[string]int
  chararray := strings.Split(s , "")
  var a []int
  var arranged map[int]string
  for k , v := range frequency {
      arranged[v] = k
  }
  for k := range arranged {
      a = append(a , k)
  }
  sort.Sort(sort.Reverse(sort.IntSlice{a}))
}

Let's say the Map structure is :

    "a" : 9
    "b" : 7
    "c" : 19
    "d" : 11

and I'm trying to traverse it such that the output is :

"c" : 19
"d" : 11
"a" : 9
"b" : 7

Answer 1

For example,

package main

import (
    "fmt"
    "sort"
)

type frequncy struct {
    c string
    f int
}

func frequencies(s string) []frequncy {
    m := make(map[string]int)
    for _, r := range s {
        m[string(r)]++
    }
    a := make([]frequncy, 0, len(m))
    for c, f := range m {
        a = append(a, frequncy{c: c, f: f})
    }
    sort.Slice(a, func(i, j int) bool { return a[i].f > a[j].f })
    return a
}

func main() {
    s := "aaaaabcbcbcbzxyyxzzsoaz"
    fmt.Println(s)
    f := frequencies(s)
    fmt.Println(f)
}

Playground: https://play.golang.org/p/d9i3yL1x4K

Output:

aaaaabcbcbcbzxyyxzzsoaz
[{a 6} {b 4} {z 4} {c 3} {x 2} {y 2} {s 1} {o 1}]