2.2 KiB
2.2 KiB
fastrand
A simple and fast random number generator.
The implementation uses Wyrand, a simple and fast generator but not cryptographically secure.
Examples
Flip a coin:
if fastrand::bool() {
println!("heads");
} else {
println!("tails");
}
Generate a random i32:
let num = fastrand::i32(..);
Choose a random element in an array:
let v = vec![1, 2, 3, 4, 5];
let i = fastrand::usize(..v.len());
let elem = v[i];
Shuffle an array:
let mut v = vec![1, 2, 3, 4, 5];
fastrand::shuffle(&mut v);
Generate a random Vec or String:
use std::iter::repeat_with;
let v: Vec<i32> = repeat_with(|| fastrand::i32(..)).take(10).collect();
let s: String = repeat_with(fastrand::alphanumeric).take(10).collect();
To get reproducible results on every run, initialize the generator with a seed:
// Pick an arbitrary number as seed.
fastrand::seed(7);
// Now this prints the same number on every run:
println!("{}", fastrand::u32(..));
To be more efficient, create a new Rng instance instead of using the thread-local
generator:
use std::iter::repeat_with;
let rng = fastrand::Rng::new();
let mut bytes: Vec<u8> = repeat_with(|| rng.u8(..)).take(10_000).collect();
License
Licensed under either of
- Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
- MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)
at your option.
Contribution
Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.