Overview

‘mat/rand’ package of golang contains a Intn function that can be used to generate a pseudo-random number between [0,n). Bracket at the end means that n is exclusive. This function can be utilized to pick a random element in an array or slice of int or string.

To know more about what pseudo-random number means, checkout this post – https://golangbyexample.com/generate-random-number-golang

Below is the signature of this method. It takes input a number n and will return a number x in range 0<=x<n.

func Intn(n int) int

Code

We can directly index an element in a slice of int. See below program for picking up random from a slice of int.

package main

import (
    "fmt"
    "math/rand"
)

func main() {
    in := []int{2, 5, 6}
    randomIndex := rand.Intn(len(in))
    pick := in[randomIndex]
    fmt.Println(pick)
}

Output:

Between 2, 5 or 6