I am porting some Python code to Go, and I needed to perform a in-place slice (array) shuffle. I was surprised to discover that there is none !!!
Basically, I wanted something like this in Python:
a = range(1,11)
>>> a
[1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
>>> random.shuffle(a)
>>> a
[8, 9, 2, 1, 4, 10, 7, 5, 3, 6]I then came across this post.
Basically, I implemented it using Sattolo’s variant of the Fisher–Yates shuffle algorythm.
The code is more or less like this:
package main
import (
"fmt"
"math/rand"
"time"
)
func Shuffle(a []int) {
for i := range a {
j := rand.Intn(i + 1)
a[i], a[j] = a[j], a[i]
}
}
func main() {
a := []int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}
rand.Seed(time.Now().UnixNano())
Shuffle(a)
fmt.Println(a)
}Here is a sample output:
$ go run myshuffle.go
[7 10 8 2 5 1 4 6 9 3]And here is the Gist and a Golang Payground.