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53 строки
1.5 KiB
Markdown
53 строки
1.5 KiB
Markdown
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rand
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====
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A Rust library for random number generators and other randomness functionality.
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[![Build Status](https://travis-ci.org/rust-lang-nursery/rand.svg?branch=master)](https://travis-ci.org/rust-lang-nursery/rand)
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[![Build status](https://ci.appveyor.com/api/projects/status/rm5c9o33k3jhchbw?svg=true)](https://ci.appveyor.com/project/alexcrichton/rand)
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[Documentation](https://doc.rust-lang.org/rand)
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## Usage
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Add this to your `Cargo.toml`:
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```toml
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[dependencies]
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rand = "0.3"
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```
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and this to your crate root:
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```rust
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extern crate rand;
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```
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## Examples
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There is built-in support for a random number generator (RNG) associated with each thread stored in thread-local storage. This RNG can be accessed via thread_rng, or used implicitly via random. This RNG is normally randomly seeded from an operating-system source of randomness, e.g. /dev/urandom on Unix systems, and will automatically reseed itself from this source after generating 32 KiB of random data.
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```rust
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let tuple = rand::random::<(f64, char)>();
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println!("{:?}", tuple)
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```
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```rust
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use rand::Rng;
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let mut rng = rand::thread_rng();
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if rng.gen() { // random bool
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println!("i32: {}, u32: {}", rng.gen::<i32>(), rng.gen::<u32>())
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}
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```
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It is also possible to use other RNG types, which have a similar interface. The following uses the "ChaCha" algorithm instead of the default.
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```rust
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use rand::{Rng, ChaChaRng};
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let mut rng = rand::ChaChaRng::new_unseeded();
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println!("i32: {}, u32: {}", rng.gen::<i32>(), rng.gen::<u32>())
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```
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