# [−][src]Crate fastrand

A simple and fast random number generator.

The implementation uses PCG XSH RR 64/32, a simple and fast generator but not cryptographically secure.

# Examples

Flip a coin:

```if fastrand::bool() {
} 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();```

## Structs

 Rng A random number generator.

## Functions

 alphabetic Generates a random `char` in ranges a-z and A-Z. alphanumeric Generates a random `char` in ranges a-z, A-Z and 0-9. bool Generates a random `bool`. digit Generates a random digit in the given `base`. f32 Generates a random `f32` in range `0..1`. f64 Generates a random `f64` in range `0..1`. i8 Generates a random `i8` in the given range. i16 Generates a random `i16` in the given range. i32 Generates a random `i32` in the given range. i64 Generates a random `i64` in the given range. i128 Generates a random `i128` in the given range. isize Generates a random `isize` in the given range. lowercase Generates a random `char` in range a-z. seed Initializes the thread-local generator with the given seed. shuffle Shuffles a slice randomly. u8 Generates a random `u8` in the given range. u16 Generates a random `u16` in the given range. u32 Generates a random `u32` in the given range. u64 Generates a random `u64` in the given range. u128 Generates a random `u128` in the given range. uppercase Generates a random `char` in range A-Z. usize Generates a random `usize` in the given range.