package main
import (
"fmt"
"sort"
)
type byLength []string
func (s byLength) Len() int {
return len(s)
}
func (s byLength) Swap(i, j int) {
s[i], s[j] = s[j], s[i]
}
func (s byLength) Less(i, j int) bool {
return len(s[i]) < len(s[j])
}
func main() {
fruits := []string{"peach", "banana", "kiwi"}
sort.Sort(byLength(fruits))
fmt.Println(fruits)
}$ go run sorting-by-functions.go
[kiwi peach banana]