Go con Ejemplos: Random Numbers

Go’s math/rand package provides pseudorandom number generation.

package main
import "fmt"
import "math/rand"
func main() {

For example, rand.Intn returns a random int n, 0 <= n < 100.

    fmt.Print(rand.Intn(100), ",")
    fmt.Print(rand.Intn(100))
    fmt.Println()

rand.Float64 returns a float64 f, 0.0 <= f < 1.0.

    fmt.Println(rand.Float64())

This can be used to generate random floats in other ranges, for example 5.0 <= f' < 10.0.

    fmt.Print((rand.Float64()*5)+5, ",")
    fmt.Print((rand.Float64() * 5) + 5)
    fmt.Println()

To make the pseudorandom generator deterministic, give it a well-known seed.

    s1 := rand.NewSource(42)
    r1 := rand.New(s1)

Call the resulting rand.Source just like the functions on the rand package.

    fmt.Print(r1.Intn(100), ",")
    fmt.Print(r1.Intn(100))
    fmt.Println()

If you seed a source with the same number, it produces the same sequence of random numbers.

    s2 := rand.NewSource(42)
    r2 := rand.New(s2)
    fmt.Print(r2.Intn(100), ",")
    fmt.Print(r2.Intn(100))
    fmt.Println()
}
$ go run random-numbers.go 
81,87
0.6645600532184904
7.123187485356329,8.434115364335547
5,87
5,87

See the math/rand package docs for references on other random quantities that Go can provide.

Siguiente ejemplo: Extracción de números de cadenas de texto.