Crate rand

Utilities for random number generation

Rand provides utilities to generate random numbers, to convert them to useful types and distributions, and some randomness-related algorithms.

Quick Start

// The prelude import enables methods we use below, specifically
// Rng::random, Rng::sample, SliceRandom::shuffle and IndexedRandom::choose.
use rand::prelude::*;

// Get an RNG:
let mut rng = rand::rng();

// Try printing a random unicode code point (probably a bad idea)!
println!("char: '{}'", rng.random::<char>());
// Try printing a random alphanumeric value instead!
println!("alpha: '{}'", rng.sample(rand::distr::Alphanumeric) as char);

// Generate and shuffle a sequence:
let mut nums: Vec<i32> = (1..100).collect();
nums.shuffle(&mut rng);
// And take a random pick (yes, we didn't need to shuffle first!):
let _ = nums.choose(&mut rng);

The Book

For the user guide and further documentation, please read The Rust Rand Book.

Modules

• distr
  Generating random samples from probability distributions
• prelude
  Convenience re-export of common members
• rngs
  Random number generators and adapters
• seq
  Sequence-related functionality

Traits

• CryptoRng
  A marker trait used to indicate that an RngCore implementation is supposed to be cryptographically secure.
• Fill
  Types which may be filled with random data
• Rng
  User-level interface for RNGs
• RngCore
  Implementation-level interface for RNGs
• SeedableRng
  A random number generator that can be explicitly seeded.
• TryCryptoRng
  A marker trait used to indicate that a TryRngCore implementation is supposed to be cryptographically secure.
• TryRngCore
  A potentially fallible variant of RngCore

Functions

• fill
  Fill any type implementing Fill with random data
• random
  Generate a random value using the thread-local random number generator.
• random_bool
  Return a bool with a probability p of being true.
• random_iter
  Return an iterator over random() variates
• random_range
  Generate a random value in the given range using the thread-local random number generator.
• random_ratio
  Return a bool with a probability of numerator/denominator of being true.
• rng
  Access a fast, pre-initialized generator
• thread_rngDeprecated
  Access the thread-local generator