Generating Random Numbers in Golang

Random numbers play an important role in many applications, from computer games to cryptography. Go has a built-in package called "math/rand" that provides a suite of functions to generate random numbers. In this article, we will explore how to use the "math/rand" package to generate random numbers in Go.

Generating a Random Integer

To generate a random integer, we can use the "Intn()" function from the "math/rand" package. The "Intn()" function takes an integer n as its argument and returns a random integer between 0 and n-1.

Example

package main

import (
   "fmt"
   "math/rand"
)

func main() {
   // Generating a random integer between 0 and 99
   randomInt := rand.Intn(100)
   fmt.Println(randomInt)
}

Output

81

Generating a Random Float

To generate a random floating-point number, we can use the "Float64()" function from the "math/rand" package. The "Float64()" function returns a random float between 0.0 and 1.0.

Example

package main

import (
   "fmt"
   "math/rand"
)

func main() {
   // Generating a random float between 0.0 and 1.0
   randomFloat := rand.Float64()
   fmt.Println(randomFloat)
}

Output

0.6046602879796196

Setting a Seed Value

To generate the same sequence of random numbers each time the program is run, we can set a seed value using the "Seed()" function from the "math/rand" package. The "Seed()" function takes an integer as its argument and initializes the random number generator.

Example

package main

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

func main() {
   // Setting a seed value to generate a different sequence of random numbers each time
   rand.Seed(time.Now().UnixNano())

   // Generating a random integer between 0 and 99
   randomInt := rand.Intn(100)
   fmt.Println(randomInt)

   // Generating a random float between 0.0 and 1.0
   randomFloat := rand.Float64()
   fmt.Println(randomFloat)
}

Output

56
0.295370367780173

Generating a Random Permutation

To generate a random permutation of a slice, we can use the "Perm()" function from the "math/rand" package. The "Perm()" function takes an integer n as its argument and returns a random permutation of the integers [0, n).

Example

package main

import (
   "fmt"
   "math/rand"
)

func main() {
   // Generating a random permutation of integers [0, 5)
   perm := rand.Perm(5)
   fmt.Println(perm)
}

Output

[0 4 2 3 1]

Conclusion

In this article, we have explored how to generate random numbers in Go using the "math/rand" package. We learned how to generate random integers and floating-point numbers, set a seed value to generate the same sequence of random numbers, and generate random permutations of slices.