rand package - math/rand - pkg.go.dev

func ExpFloat64 ¶

func ExpFloat64() float64

ExpFloat64 returns an exponentially distributed float64 in the range (0, +math.MaxFloat64] with an exponential distribution whose rate parameter (lambda) is 1 and whose mean is 1/lambda (1) from the default Source. To produce a distribution with a different rate parameter, callers can adjust the output using:

sample = ExpFloat64() / desiredRateParameter

func Float32 ¶

func Float32() float32

Float32 returns, as a float32, a pseudo-random number in the half-open interval [0.0,1.0) from the default Source.

func Float64 ¶

func Float64() float64

Float64 returns, as a float64, a pseudo-random number in the half-open interval [0.0,1.0) from the default Source.

func Int ¶

func Int() int

Int returns a non-negative pseudo-random int from the default Source.

func Int31 ¶

func Int31() int32

Int31 returns a non-negative pseudo-random 31-bit integer as an int32 from the default Source.

func Int31n ¶

func Int31n(n int32) int32

Int31n returns, as an int32, a non-negative pseudo-random number in the half-open interval [0,n) from the default Source. It panics if n <= 0.

func Int63 ¶

func Int63() int64

Int63 returns a non-negative pseudo-random 63-bit integer as an int64 from the default Source.

func Int63n ¶

func Int63n(n int64) int64

Int63n returns, as an int64, a non-negative pseudo-random number in the half-open interval [0,n) from the default Source. It panics if n <= 0.

func Intn ¶

func Intn(n int) int

Intn returns, as an int, a non-negative pseudo-random number in the half-open interval [0,n) from the default Source. It panics if n <= 0.

Example ¶

func NormFloat64 ¶

func NormFloat64() float64

NormFloat64 returns a normally distributed float64 in the range [-math.MaxFloat64, +math.MaxFloat64] with standard normal distribution (mean = 0, stddev = 1) from the default Source. To produce a different normal distribution, callers can adjust the output using:

sample = NormFloat64() * desiredStdDev + desiredMean

func Perm ¶

func Perm(n int) []int

Perm returns, as a slice of n ints, a pseudo-random permutation of the integers in the half-open interval [0,n) from the default Source.

Example ¶

func Read ¶ added in go1.6

func Read(p []byte) (n int, err error)

Read generates len(p) random bytes from the default Source and writes them into p. It always returns len(p) and a nil error. Read, unlike the Rand.Read method, is safe for concurrent use.

func Seed ¶

func Seed(seed int64)

Seed uses the provided seed value to initialize the default Source to a deterministic state. If Seed is not called, the generator behaves as if seeded by Seed(1). Seed values that have the same remainder when divided by 2³¹-1 generate the same pseudo-random sequence. Seed, unlike the Rand.Seed method, is safe for concurrent use.

func Shuffle ¶ added in go1.10

func Shuffle(n int, swap func(i, j int))

Shuffle pseudo-randomizes the order of elements using the default Source. n is the number of elements. Shuffle panics if n < 0. swap swaps the elements with indexes i and j.

Example ¶

Example (SlicesInUnison) ¶

func Uint32 ¶

func Uint32() uint32

Uint32 returns a pseudo-random 32-bit value as a uint32 from the default Source.

func Uint64 ¶ added in go1.8

func Uint64() uint64

Uint64 returns a pseudo-random 64-bit value as a uint64 from the default Source.