Example of sorting a map via different sorting implementations

MapSort.go

package main

import (
	"fmt"
	"sort"
)

type Person struct {
	Title     string
	FirstName string
	LastName  string
	Address
}

type Address struct {
	HouseNumber int
	Street      string
	Town        string
	PostCode    string
}

// different sort implementations

type BySurname map[int]Person

func (b BySurname) Len() int           { return len(b) }
func (b BySurname) Swap(i, j int)      { b[i], b[j] = b[j], b[i] }
func (b BySurname) Less(i, j int) bool { return b[i].LastName < b[j].LastName }

type ByHouseNumber map[int]Person

func (b ByHouseNumber) Len() int           { return len(b) }
func (b ByHouseNumber) Swap(i, j int)      { b[i], b[j] = b[j], b[i] }
func (b ByHouseNumber) Less(i, j int) bool { return b[i].HouseNumber < b[j].HouseNumber }

type ByStreet map[int]Person

func (b ByStreet) Len() int           { return len(b) }
func (b ByStreet) Swap(i, j int)      { b[i], b[j] = b[j], b[i] }
func (b ByStreet) Less(i, j int) bool { return b[i].Street < b[j].Street }

func main() {

	people := map[int]Person{
		0: Person{"Mr", "Joe", "Bloggs", Address{30, "Rose Lea", "Preston", "PR2 9LA"}},
		1: Person{"Mr", "John", "Smith", Address{6, "Samuel Street", "Preston", "PR1 4YJ"}},
		2: Person{"Mr", "Dave", "Jones", Address{54, "St. Vincents Road", "Preston", "PR3 14Y"}},
	}

	sort.Sort(ByHouseNumber(people)) // or sort.Sort(BySurname(people)) or sort.Sort(ByStreet(people))

	// iterate over the map  with a traditional for loop - don't user (for i, _ := range) as return order is randomised
	for i := 0; i < len(people); i++ {
		fmt.Printf("%s %s %s, %d, %s, %s, %s\n",
			people[i].Title,
			people[i].FirstName,
			people[i].LastName,
			people[i].HouseNumber,
			people[i].Street,
			people[i].Town,
			people[i].PostCode)
	}
}