Knuth Fisher-Yates shuffle for Go (golang)

knuth.go

// implements Knuth or Fisher-Yates shuffle
package knuth

import (
    "math/rand"
    "time"
)

func init() {
    rand.Seed(time.Now().UTC().UnixNano())
}

func Shuffle(slc []interface{}) {
    N := len(slc)
    for i := 0; i < N; i++ {
        // choose index uniformly in [i, N-1]
        r := i + rand.Intn(N-i)
        slc[r], slc[i] = slc[i], slc[r]
    }
}

func ShuffleInts(slc []int) {
    N := len(slc)
    for i := 0; i < N; i++ {
        // choose index uniformly in [i, N-1]
        r := i + rand.Intn(N-i)
        slc[r], slc[i] = slc[i], slc[r]
    }
}

func ShuffleStrings(slc []string) {
    N := len(slc)
    for i := 0; i < N; i++ {
        // choose index uniformly in [i, N-1]
        r := i + rand.Intn(N-i)
        slc[r], slc[i] = slc[i], slc[r]
    }
}

rand.Seed should not be called in the package.
If it has to be done, it must be done just once per program in the main package. Because if every package that uses rand calls Seed, it may be called many times, while once is enough.