Sort a map of string to int type, by decending order of the value of the map.

map.go

package main

func ConvertMapToKVSlice(m map[string]int) (kv []KV) {
	for k, v := range m {
		kv = append(kv, KV{k, v})
	}
	return
}

type KV struct {
	Key   string
	Value int
}

// SortedMapByValue is a sorted map by decreasing value
// POC- https://play.golang.org/p/mZN4uSa5pG0
type SortedMapByValue []KV

// Len is the number of elements in the collection.
func (s SortedMapByValue) Len() int {
	return len(s)
}

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

// we want it to be in decreasing order of the values
func (s SortedMapByValue) Less(i int, j int) bool {
	return s[i].Value > s[j].Value
}

// Swap swaps the elements with indexes i and j.
func (s SortedMapByValue) Swap(i int, j int) {
	s[i], s[j] = s[j], s[i]
}

func (s SortedMapByValue) FetchKey(pos int) string {
	if len(s) < pos {
		return ""
	}
	return s[pos].Key
}

func (s SortedMapByValue) FetchVal(pos int) int {
	if len(s) < pos {
		return 0
	}
	return s[pos].Value
}