# Algorithms

Examples Filter
Sometimes we’ll want to sort a collection by something other than its natural order. For example, suppose we wanted to sort strings by their length instead of alphabetically. Here’s an example of custom sorts in Go.
``````package main

import (
"fmt"
"sort"
)

type byLength []string

// We implement sort.Interface - Len, Less, and Swap -
// on our type so we can use the sort package’s generic Sort function.
// Len and Swap will usually be similar across types and
// Less will hold the actual custom sorting logic.
// In our case we want to sort in order of increasing string length,
// so we use len(s[i]) and len(s[j]) here.
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])
}

// With all of this in place, we can now implement our custom sort by converting
// the original fruits slice to byLength, and then use sort.Sort on that typed slice.
func main() {
fruits := []string{"peach", "banana", "kiwi"}
sort.Sort(byLength(fruits))
fmt.Println(fruits)
}``````