rand::StdRng - Rust
Description: API documentation for the Rust `StdRng` struct in crate `rand`.
Keywords: rust, rustlang, rust-lang, StdRng

# Struct rand::StdRng [−] [src]

    pub struct StdRng { /* fields omitted */ }

The standard RNG. This is designed to be efficient on the current platform.

## Methods

### `impl StdRng`
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#### `fn new() -> Result<StdRng>`
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Create a randomly seeded instance of `StdRng`.

This is a very expensive operation as it has to read randomness from the operating system and use this in an expensive seeding operation. If one is only generating a small number of random numbers, or doesn't need the utmost speed for generating each number, `thread_rng` and/or `random` may be more appropriate.

Reading the randomness from the OS may fail, and any error is propagated via the `io::Result` return value.

## Trait Implementations

### `impl Copy for StdRng`
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### `impl Clone for StdRng`
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#### `fn clone(&self) -> StdRng`
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Returns a copy of the value. Read more

#### `fn clone_from(&mut self, source: &Self)`
1.0.0
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Performs copy-assignment from `source`. Read more

### `impl Debug for StdRng`
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#### `fn fmt(&self, __arg_0: &mut Formatter) -> Result`
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Formats the value using the given formatter.

### `impl Rng for StdRng`
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#### `fn next_u32(&mut self) -> u32`
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Return the next random u32. Read more

#### `fn next_u64(&mut self) -> u64`
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Return the next random u64. Read more

#### `fn next_f32(&mut self) -> f32`
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Return the next random f32 selected from the half-open interval `[0, 1)`. Read more

#### `fn next_f64(&mut self) -> f64`
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Return the next random f64 selected from the half-open interval `[0, 1)`. Read more

#### `fn fill_bytes(&mut self, dest: &mut [u8])`
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Fill `dest` with random data. Read more

#### `fn gen<T: Rand>(&mut self) -> T where
Self: Sized,`
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Return a random value of a `Rand` type. Read more

#### `fn gen_iter<'a, T: Rand>(&'a mut self) -> Generator<'a, T, Self> where
Self: Sized,`
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Return an iterator that will yield an infinite number of randomly generated items. Read more

#### `fn gen_range<T: PartialOrd + SampleRange>(&mut self, low: T, high: T) -> T where
Self: Sized,`
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Generate a random value in the range [`low`, `high`). Read more

#### `fn gen_weighted_bool(&mut self, n: u32) -> bool where
Self: Sized,`
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Return a bool with a 1 in n chance of true Read more

#### `fn gen_ascii_chars<'a>(&'a mut self) -> AsciiGenerator<'a, Self> where
Self: Sized,`
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Return an iterator of random characters from the set A-Z,a-z,0-9. Read more

#### `fn choose<'a, T>(&mut self, values: &'a [T]) -> Option<&'a T> where
Self: Sized,`
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Return a random element from `values`. Read more

#### `fn choose_mut<'a, T>(&mut self, values: &'a mut [T]) -> Option<&'a mut T> where
Self: Sized,`
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Return a mutable pointer to a random element from `values`. Read more

#### `fn shuffle<T>(&mut self, values: &mut [T]) where
Self: Sized,`
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Shuffle a mutable slice in place. Read more

### `impl<'a> SeedableRng<&'a [usize]> for StdRng`
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#### `fn reseed(&mut self, seed: &'a [usize])`
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Reseed an RNG with the given seed. Read more

#### `fn from_seed(seed: &'a [usize]) -> StdRng`
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Create a new RNG with the given seed. Read more

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