Golang : How to shuffle elements in array or slice?


Tags : golang shuffle array slice elements

Problem :

You have an array or slice with elements in natural order and you want to shuffle the elements.

Solution :

Use rand.Seed function to randomize the elements position inside the array or slice.

For example :

 package main

 import (
  "fmt"
  "math/rand"
  "time"
 )

 func shuffle(arr []int) {
  t := time.Now()
  rand.Seed(int64(t.Nanosecond())) // no shuffling without this line

  for i := len(arr) - 1; i > 0; i-- {
 j := rand.Intn(i)
 arr[i], arr[j] = arr[j], arr[i]
  }
 }

 func main() {

  //list := rand.Perm(25)
  list := []int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}
  fmt.Printf("Original : %v\n", list)

  shuffledList := list

  shuffle(shuffledList)
  fmt.Printf("Shuffled : %v\n", shuffledList)

 }

Output :

Original : [1 2 3 4 5 6 7 8 9 10]

Shuffled : [10 3 9 8 2 1 4 6 7 5]

  See also : Golang : Generate random elements without repetition or duplicate



Tags : golang shuffle array slice elements

By Adam Ng

IF you gain some knowledge or the information here solved your programming problem. Please consider donating to the less fortunate or some charities that you like. Apart from donation, planting trees, volunteering or reducing your carbon footprint will be great too.


Advertisement