Trait std::rand::RngDeprecated
[-] [+]
[src]
pub trait Rng {
fn next_u32(&mut self) -> u32;
fn next_u64(&mut self) -> u64 { ... }
fn next_f32(&mut self) -> f32 { ... }
fn next_f64(&mut self) -> f64 { ... }
fn fill_bytes(&mut self, dest: &mut [u8]) { ... }
fn gen<T>(&mut self) -> T where T: Rand { ... }
fn gen_iter<T>(&'a mut self) -> Generator<'a, T, Self> where T: Rand { ... }
fn gen_range<T>(&mut self, low: T, high: T) -> T where T: SampleRange, T: PartialOrd<T> { ... }
fn gen_weighted_bool(&mut self, n: usize) -> bool { ... }
fn gen_ascii_chars(&'a mut self) -> AsciiGenerator<'a, Self> { ... }
fn choose<T>(&mut self, values: &'a [T]) -> Option<&'a T> { ... }
fn shuffle<T>(&mut self, values: &mut [T]) { ... }
}A random number generator.
Required Methods
fn next_u32(&mut self) -> u32
Return the next random u32.
This rarely needs to be called directly, prefer r.gen() to
r.next_u32().
Provided Methods
fn next_u64(&mut self) -> u64
Return the next random u64.
By default this is implemented in terms of next_u32. An
implementation of this trait must provide at least one of
these two methods. Similarly to next_u32, this rarely needs
to be called directly, prefer r.gen() to r.next_u64().
fn next_f32(&mut self) -> f32
Return the next random f32 selected from the half-open
interval [0, 1).
By default this is implemented in terms of next_u32, but a
random number generator which can generate numbers satisfying
the requirements directly can overload this for performance.
It is required that the return value lies in [0, 1).
See Closed01 for the closed interval [0,1], and
Open01 for the open interval (0,1).
fn next_f64(&mut self) -> f64
Return the next random f64 selected from the half-open
interval [0, 1).
By default this is implemented in terms of next_u64, but a
random number generator which can generate numbers satisfying
the requirements directly can overload this for performance.
It is required that the return value lies in [0, 1).
See Closed01 for the closed interval [0,1], and
Open01 for the open interval (0,1).
fn fill_bytes(&mut self, dest: &mut [u8])
Fill dest with random data.
This has a default implementation in terms of next_u64 and
next_u32, but should be overridden by implementations that
offer a more efficient solution than just calling those
methods repeatedly.
This method does not have a requirement to bear any fixed
relationship to the other methods, for example, it does not
have to result in the same output as progressively filling
dest with self.gen::<u8>(), and any such behaviour should
not be relied upon.
This method should guarantee that dest is entirely filled
with new data, and may panic if this is impossible
(e.g. reading past the end of a file that is being used as the
source of randomness).
Example
fn main() { use std::rand::{thread_rng, Rng}; let mut v = [0u8; 13579]; thread_rng().fill_bytes(&mut v); println!("{:?}", v.as_slice()); }use std::rand::{thread_rng, Rng}; let mut v = [0u8; 13579]; thread_rng().fill_bytes(&mut v); println!("{:?}", v.as_slice());
fn gen<T>(&mut self) -> T where T: Rand
Return a random value of a Rand type.
Example
fn main() { use std::rand::{thread_rng, Rng}; let mut rng = thread_rng(); let x: uint = rng.gen(); println!("{}", x); println!("{:?}", rng.gen::<(f64, bool)>()); }use std::rand::{thread_rng, Rng}; let mut rng = thread_rng(); let x: uint = rng.gen(); println!("{}", x); println!("{:?}", rng.gen::<(f64, bool)>());
fn gen_iter<T>(&'a mut self) -> Generator<'a, T, Self> where T: Rand
Return an iterator that will yield an infinite number of randomly generated items.
Example
fn main() { use std::rand::{thread_rng, Rng}; let mut rng = thread_rng(); let x = rng.gen_iter::<uint>().take(10).collect::<Vec<uint>>(); println!("{:?}", x); println!("{:?}", rng.gen_iter::<(f64, bool)>().take(5) .collect::<Vec<(f64, bool)>>()); }use std::rand::{thread_rng, Rng}; let mut rng = thread_rng(); let x = rng.gen_iter::<uint>().take(10).collect::<Vec<uint>>(); println!("{:?}", x); println!("{:?}", rng.gen_iter::<(f64, bool)>().take(5) .collect::<Vec<(f64, bool)>>());
fn gen_range<T>(&mut self, low: T, high: T) -> T where T: SampleRange, T: PartialOrd<T>
Generate a random value in the range [low, high).
This is a convenience wrapper around
distributions::Range. If this function will be called
repeatedly with the same arguments, one should use Range, as
that will amortize the computations that allow for perfect
uniformity, as they only happen on initialization.
Panics
Panics if low >= high.
Example
fn main() { use std::rand::{thread_rng, Rng}; let mut rng = thread_rng(); let n: uint = rng.gen_range(0, 10); println!("{}", n); let m: f64 = rng.gen_range(-40.0f64, 1.3e5f64); println!("{}", m); }use std::rand::{thread_rng, Rng}; let mut rng = thread_rng(); let n: uint = rng.gen_range(0, 10); println!("{}", n); let m: f64 = rng.gen_range(-40.0f64, 1.3e5f64); println!("{}", m);
fn gen_weighted_bool(&mut self, n: usize) -> bool
Return a bool with a 1 in n chance of true
Example
fn main() { use std::rand::{thread_rng, Rng}; let mut rng = thread_rng(); println!("{}", rng.gen_weighted_bool(3)); }use std::rand::{thread_rng, Rng}; let mut rng = thread_rng(); println!("{}", rng.gen_weighted_bool(3));
fn gen_ascii_chars(&'a mut self) -> AsciiGenerator<'a, Self>
Return an iterator of random characters from the set A-Z,a-z,0-9.
Example
fn main() { use std::rand::{thread_rng, Rng}; let s: String = thread_rng().gen_ascii_chars().take(10).collect(); println!("{}", s); }use std::rand::{thread_rng, Rng}; let s: String = thread_rng().gen_ascii_chars().take(10).collect(); println!("{}", s);
fn choose<T>(&mut self, values: &'a [T]) -> Option<&'a T>
Return a random element from values.
Return None if values is empty.
Example
fn main() { use std::rand::{thread_rng, Rng}; let choices = [1, 2, 4, 8, 16, 32]; let mut rng = thread_rng(); println!("{:?}", rng.choose(&choices)); assert_eq!(rng.choose(&choices[..0]), None); }use std::rand::{thread_rng, Rng}; let choices = [1, 2, 4, 8, 16, 32]; let mut rng = thread_rng(); println!("{:?}", rng.choose(&choices)); assert_eq!(rng.choose(&choices[..0]), None);
fn shuffle<T>(&mut self, values: &mut [T])
Shuffle a mutable slice in place.
Example
fn main() { use std::rand::{thread_rng, Rng}; let mut rng = thread_rng(); let mut y = [1, 2, 3]; rng.shuffle(&mut y); println!("{:?}", y.as_slice()); rng.shuffle(&mut y); println!("{:?}", y.as_slice()); }use std::rand::{thread_rng, Rng}; let mut rng = thread_rng(); let mut y = [1, 2, 3]; rng.shuffle(&mut y); println!("{:?}", y.as_slice()); rng.shuffle(&mut y); println!("{:?}", y.as_slice());