Go sort map

sortmap.go

package main

import (
	"fmt"
	"sort"
)

type Shop struct {
	Code string
}

type Shops []*Shop

func (d Shops) Len() int {
	return len(d)
}
func (d Shops) Swap(i, j int) {
	d[i], d[j] = d[j], d[i]
}
func (d Shops) Less(i, j int) bool {
	return d[i].Code < d[j].Code
}

func main() {

	shopMap := make(map[string]*Shop)

	shopMap["xx"] = &Shop{Code: "xx"}
	shopMap["hoge"] = &Shop{Code: "hoge"}
	shopMap["fuga"] = &Shop{Code: "fuga"}

	var keys Shops
	for _, s := range shopMap {
		keys = append(keys, s)
	}

	sort.Sort(keys)

	fmt.Printf("%t", keys)
}