---
title: rand
slug: reference/rand
docTags: 
createdAt: 2025-09-24T15:42:57.160Z
---

## Module - "rand"

### Functions

- `seed(seed int)`: has no effect. It wraps a function that Go turns into a no-op for modern modules, so it cannot make a calculation reproducible. For a deterministic sequence, create your own generator with `rand.rand(seed)` and use the functions on it.
- `exp_float() => float`: 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.
- `float() => float`: returns, as a float64, a pseudo-random number in \[0.0,1.0) from the default Source.
- `int() => int`: returns a non-negative pseudo-random 63-bit integer as an int64 from the default Source.
- `intn(n int) => int`: returns, as an int64, a non-negative pseudo-random number in \[0,n) from the default Source. It panics if n \<= 0.
- `norm_float() => float`: returns a normally distributed float64 in the range \[-math.MaxFloat64, +math.MaxFloat64] with standard normal distribution (mean = 0, stddev = 1) from the default Source.
- `perm(n int) => [int]`: returns, as a slice of n ints, a pseudo-random permutation of the integers \[0,n) from the default Source.
- `read(p bytes) => int/error`: generates len(p) random bytes from the default Source and writes them into p. It always returns len(p) and a nil error.
- `rand(src_seed int) => Rand`: returns a new Rand that uses random values from src to generate other random values.

### Rand

- `seed(seed int)`: uses the provided seed value to initialize the default Source to a deterministic state.
- `exp_float() => float`: 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.
- `float() => float`: returns, as a float64, a pseudo-random number in \[0.0,1.0) from the default Source.
- `int() => int`: returns a non-negative pseudo-random 63-bit integer as an int64 from the default Source.
- `intn(n int) => int`: returns, as an int64, a non-negative pseudo-random number in \[0,n) from the default Source. It panics if n \<= 0.
- `norm_float() => float`: returns a normally distributed float64 in the range \[-math.MaxFloat64, +math.MaxFloat64] with standard normal distribution (mean = 0, stddev = 1) from the default Source.
- `perm(n int) => [int]`: returns, as a slice of n ints, a pseudo-random permutation of the integers \[0,n) from the default Source.
- `read(p bytes) => int/error`: generates len(p) random bytes from the default Source and writes them into p. It always returns len(p) and a nil error.