Trait rand::seq::IteratorRandom

pub trait IteratorRandom: Iterator + Sized {
    fn choose<R: ?Sized>(self, rng: &mut R) -> Option<Self::Item>
    where
        R: Rng,
    { ... }
    fn choose_multiple_fill<R: ?Sized>(
        self, 
        rng: &mut R, 
        buf: &mut [Self::Item]
    ) -> usize
    where
        R: Rng,
    { ... }
    fn choose_multiple<R: ?Sized>(
        self, 
        rng: &mut R, 
        amount: usize
    ) -> Vec<Self::Item>
    where
        R: Rng,
    { ... }
}

Extension trait on iterators, providing random sampling methods.

Provided methods

fn choose<R: ?Sized>(self, rng: &mut R) -> Option<Self::Item> where
    R: Rng, 

Choose one element at random from the iterator. If you have a slice, it's significantly faster to call the choose or choose_mut functions using the slice instead.

Returns None if and only if the iterator is empty.

Complexity is O(n), where n is the length of the iterator. This likely consumes multiple random numbers, but the exact number is unspecified.

fn choose_multiple_fill<R: ?Sized>(
    self,
    rng: &mut R,
    buf: &mut [Self::Item]
) -> usize where
    R: Rng, 

Collects amount values at random from the iterator into a supplied buffer.

Although the elements are selected randomly, the order of elements in the buffer is neither stable nor fully random. If random ordering is desired, shuffle the result.

Returns the number of elements added to the buffer. This equals amount unless the iterator contains insufficient elements, in which case this equals the number of elements available.

Complexity is O(n) where n is the length of the iterator.

fn choose_multiple<R: ?Sized>(
    self,
    rng: &mut R,
    amount: usize
) -> Vec<Self::Item> where
    R: Rng, 

Collects amount values at random from the iterator into a vector.

This is equivalent to choose_multiple_fill except for the result type.

Although the elements are selected randomly, the order of elements in the buffer is neither stable nor fully random. If random ordering is desired, shuffle the result.

The length of the returned vector equals amount unless the iterator contains insufficient elements, in which case it equals the number of elements available.

Complexity is O(n) where n is the length of the iterator.

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Implementors

impl<I> IteratorRandom for I where
    I: Iterator + Sized, 

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