Sorting slices and user-defined collections in Go

it couldn’t be better

https://golang.org/pkg/sort/

package main

import (
    "fmt"
    "sort"
)

type Grams int

func (g Grams) String() string { return fmt.Sprintf("%dg", int(g)) }

type Organ struct {
    Name   string
    Weight Grams
}

type Organs []*Organ

func (s Organs) Len() int      { return len(s) }
func (s Organs) Swap(i, j int) { s[i], s[j] = s[j], s[i] }

// ByName implements sort.Interface by providing Less and using the Len and
// Swap methods of the embedded Organs value.
type ByName struct{ Organs }

func (s ByName) Less(i, j int) bool { return s.Organs[i].Name < s.Organs[j].Name }

// ByWeight implements sort.Interface by providing Less and using the Len and
// Swap methods of the embedded Organs value.
type ByWeight struct{ Organs }

func (s ByWeight) Less(i, j int) bool { return s.Organs[i].Weight < s.Organs[j].Weight }

func main() {
    s := []*Organ{
        {"brain", 1340},
        {"heart", 290},
        {"liver", 1494},
        {"pancreas", 131},
        {"prostate", 62},
        {"spleen", 162},
    }

    sort.Sort(ByWeight{s})
    fmt.Println("Organs by weight:")
    printOrgans(s)

    sort.Sort(ByName{s})
    fmt.Println("Organs by name:")
    printOrgans(s)

}

func printOrgans(s []*Organ) {
    for _, o := range s {
        fmt.Printf("%-8s (%v)\n", o.Name, o.Weight)
    }
}
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