Module rand::seq

Expand description

Sequence-related functionality

This module provides:

SliceRandom slice sampling and mutation
IteratorRandom iterator sampling
index::sample low-level API to choose multiple indices from -0..length

Also see:

crate::distributions::WeightedIndex distribution which provides -weighted index sampling.

In order to make results reproducible across 32-64 bit architectures, all -usize indices are sampled as a u32 where possible (also providing a -small performance boost in some cases).

Structs

SliceChooseIter

An iterator over multiple slice elements.

Traits

IteratorRandom

Extension trait on iterators, providing random sampling methods.

SliceRandom

Extension trait on slices, providing random mutation and sampling methods.

Enum rand::seq::index::IndexVec

source · [−]

pub enum IndexVec {
-    // some variants omitted
-}

Expand description

A vector of indices.

Multiple internal representations are possible.

Implementations

source

impl IndexVec

source

pub fn len(&self) -> usize

Returns the number of indices

source

pub fn is_empty(&self) -> bool

Returns true if the length is 0.

source

pub fn index(&self, index: usize) -> usize

Return the value at the given index.

(Note: we cannot implement std::ops::Index because of lifetime -restrictions.)

source

pub fn into_vec(self) -> Vec<usize>

Return result as a Vec<usize>. Conversion may or may not be trivial.

source

pub fn iter(&self) -> IndexVecIter<'_>ⓘNotable traits for IndexVecIter<'a>`impl<'a> Iterator for IndexVecIter<'a> type Item = usize;`

Iterate over the indices as a sequence of usize values

Trait Implementations

source

impl Clone for IndexVec

source

fn clone(&self) -> IndexVec

Returns a copy of the value. Read more

1.0.0 · source

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more

source

impl Debug for IndexVec

source

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter. Read more

source

impl From<Vec<u32, Global>> for IndexVec

source

fn from(v: Vec<u32>) -> Self

Converts to this type from the input type.

source

impl From<Vec<usize, Global>> for IndexVec

source

fn from(v: Vec<usize>) -> Self

Converts to this type from the input type.

source

impl IntoIterator for IndexVec

source

fn into_iter(self) -> IndexVecIntoIterⓘNotable traits for IndexVecIntoIter`impl Iterator for IndexVecIntoIter type Item = usize;`

Convert into an iterator over the indices as a sequence of usize values

type Item = usize

The type of the elements being iterated over.

type IntoIter = IndexVecIntoIter

Which kind of iterator are we turning this into?

source

impl PartialEq<IndexVec> for IndexVec

source

fn eq(&self, other: &IndexVec) -> bool

This method tests for self and other values to be equal, and is used -by ==. Read more

1.0.0 · source

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always -sufficient, and should not be overridden without very good reason. Read more

Auto Trait Implementations

impl RefUnwindSafe for IndexVec

Blanket Implementations

source

impl<T> Any for Twhere
T: 'static + ?Sized,

source

fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more

source

impl<T> Borrow<T> for Twhere
T: ?Sized,

const: unstable · source

fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more

source

impl<T> BorrowMut<T> for Twhere
T: ?Sized,

const: unstable · source

fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more

source

impl<T> From<T> for T

const: unstable · source

fn from(t: T) -> T

Returns the argument unchanged.

source

impl<T, U> Into for Twhere
U: From<T>,

const: unstable · source

fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of -From<T> for U chooses to do.

source

impl<T> ToOwned for Twhere
T: Clone,

type Owned = T

The resulting type after obtaining ownership.

source

fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more

source

fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more

source

impl<T, U> TryFrom for Twhere
U: Into<T>,

type Error = Infallible

The type returned in the event of a conversion error.

const: unstable · source

fn try_from(value: U) -> Result<T, <T as TryFrom>::Error>

Performs the conversion.

source

impl<T, U> TryInto for Twhere
U: TryFrom<T>,

type Error = >::Error

The type returned in the event of a conversion error.

const: unstable · source

fn try_into(self) -> Result<U, >::Error>

Performs the conversion.

source

impl<V, T> VZip<V> for Twhere
V: MultiLane<T>,

source

fn vzip(self) -> V

Enum rand::seq::index::IndexVecIntoIter

source · [−]

pub enum IndexVecIntoIter {
-    // some variants omitted
-}

Expand description

Return type of IndexVec::into_iter.

Trait Implementations

source

impl Clone for IndexVecIntoIter

source

fn clone(&self) -> IndexVecIntoIterⓘNotable traits for IndexVecIntoIter`impl Iterator for IndexVecIntoIter type Item = usize;`

Returns a copy of the value. Read more

1.0.0 · source

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more

source

impl Debug for IndexVecIntoIter

source

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter. Read more

source

impl ExactSizeIterator for IndexVecIntoIter

1.0.0 · source

fn len(&self) -> usize

Returns the exact remaining length of the iterator. Read more

source

fn is_empty(&self) -> bool

🔬This is a nightly-only experimental API. (exact_size_is_empty)

Returns true if the iterator is empty. Read more

source

impl Iterator for IndexVecIntoIter

type Item = usize

The type of the elements being iterated over.

source

fn next(&mut self) -> Option<Self::Item>

Advances the iterator and returns the next value. Read more

source

fn size_hint(&self) -> (usize, Option<usize>)

Returns the bounds on the remaining length of the iterator. Read more

source

fn next_chunk<const N: usize>(
&mut self
) -> Result<[Self::Item; N], IntoIter<Self::Item, N>>where
Self: Sized,

🔬This is a nightly-only experimental API. (iter_next_chunk)

Advances the iterator and returns an array containing the next N values. Read more

1.0.0 · source

fn count(self) -> usizewhere
Self: Sized,

Consumes the iterator, counting the number of iterations and returning it. Read more

1.0.0 · source

fn last(self) -> Option<Self::Item>where
Self: Sized,

Consumes the iterator, returning the last element. Read more

source

fn advance_by(&mut self, n: usize) -> Result<(), usize>

🔬This is a nightly-only experimental API. (iter_advance_by)

Advances the iterator by n elements. Read more

1.0.0 · source

fn nth(&mut self, n: usize) -> Option<Self::Item>

Returns the nth element of the iterator. Read more

1.28.0 · source

fn step_by(self, step: usize) -> StepBy<Self>where
Self: Sized,

Creates an iterator starting at the same point, but stepping by -the given amount at each iteration. Read more

1.0.0 · source

fn chain(self, other: U) -> Chain<Self, ::IntoIter>where
Self: Sized,
U: IntoIterator<Item = Self::Item>,

Takes two iterators and creates a new iterator over both in sequence. Read more

1.0.0 · source

fn zip(self, other: U) -> Zip<Self, ::IntoIter>where
Self: Sized,
U: IntoIterator,

‘Zips up’ two iterators into a single iterator of pairs. Read more

source

fn intersperse_with<G>(self, separator: G) -> IntersperseWith<Self, G>where
Self: Sized,
G: FnMut() -> Self::Item,

🔬This is a nightly-only experimental API. (iter_intersperse)

Creates a new iterator which places an item generated by separator -between adjacent items of the original iterator. Read more

1.0.0 · source

fn map<B, F>(self, f: F) -> Map<Self, F>where
Self: Sized,
F: FnMut(Self::Item) -> B,

Takes a closure and creates an iterator which calls that closure on each -element. Read more

1.21.0 · source

fn for_each<F>(self, f: F)where
Self: Sized,
F: FnMut(Self::Item),

Calls a closure on each element of an iterator. Read more

1.0.0 · source

fn filter(self, predicate: P) -> Filter<Self, P>where
Self: Sized,
P: FnMut(&Self::Item) -> bool,

Creates an iterator which uses a closure to determine if an element -should be yielded. Read more

1.0.0 · source

fn filter_map<B, F>(self, f: F) -> FilterMap<Self, F>where
Self: Sized,
F: FnMut(Self::Item) -> Option,

Creates an iterator that both filters and maps. Read more

1.0.0 · source

fn enumerate(self) -> Enumerate<Self>where
Self: Sized,

Creates an iterator which gives the current iteration count as well as -the next value. Read more

1.0.0 · source

fn peekable(self) -> Peekable<Self>where
Self: Sized,

Creates an iterator which can use the peek and peek_mut methods -to look at the next element of the iterator without consuming it. See -their documentation for more information. Read more

1.0.0 · source

fn skip_while(self, predicate: P) -> SkipWhile<Self, P>where
Self: Sized,
P: FnMut(&Self::Item) -> bool,

Creates an iterator that skips elements based on a predicate. Read more

1.0.0 · source

fn take_while(self, predicate: P) -> TakeWhile<Self, P>where
Self: Sized,
P: FnMut(&Self::Item) -> bool,

Creates an iterator that yields elements based on a predicate. Read more

1.57.0 · source

fn map_while<B, P>(self, predicate: P) -> MapWhile<Self, P>where
Self: Sized,
P: FnMut(Self::Item) -> Option,

Creates an iterator that both yields elements based on a predicate and maps. Read more

1.0.0 · source

fn skip(self, n: usize) -> Skip<Self>where
Self: Sized,

Creates an iterator that skips the first n elements. Read more

1.0.0 · source

fn take(self, n: usize) -> Take<Self>where
Self: Sized,

Creates an iterator that yields the first n elements, or fewer -if the underlying iterator ends sooner. Read more

1.0.0 · source

fn scan<St, B, F>(self, initial_state: St, f: F) -> Scan<Self, St, F>where
Self: Sized,
F: FnMut(&mut St, Self::Item) -> Option,

An iterator adapter similar to fold that holds internal state and -produces a new iterator. Read more

1.0.0 · source

fn flat_map<U, F>(self, f: F) -> FlatMap<Self, U, F>where
 Self: Sized,
 U: IntoIterator,
 F: FnMut(Self::Item) -> U,

Creates an iterator that works like map, but flattens nested structure. Read more

1.0.0 · source

fn fuse(self) -> Fuse<Self>where
Self: Sized,

Creates an iterator which ends after the first None. Read more

1.0.0 · source

fn inspect<F>(self, f: F) -> Inspect<Self, F>where
Self: Sized,
F: FnMut(&Self::Item),

Does something with each element of an iterator, passing the value on. Read more

1.0.0 · source

fn by_ref(&mut self) -> &mut Selfwhere
Self: Sized,

Borrows an iterator, rather than consuming it. Read more

1.0.0 · source

fn collect(self) -> Bwhere
B: FromIterator<Self::Item>,
Self: Sized,

Transforms an iterator into a collection. Read more

source

fn collect_into<E>(self, collection: &mut E) -> &mut Ewhere
E: Extend<Self::Item>,
Self: Sized,

🔬This is a nightly-only experimental API. (iter_collect_into)

Collects all the items from an iterator into a collection. Read more

1.0.0 · source

fn partition<B, F>(self, f: F) -> (B, B)where
 Self: Sized,
 B: Default + Extend<Self::Item>,
 F: FnMut(&Self::Item) -> bool,

Consumes an iterator, creating two collections from it. Read more

source

fn is_partitioned(self, predicate: P) -> boolwhere
Self: Sized,
P: FnMut(Self::Item) -> bool,

🔬This is a nightly-only experimental API. (iter_is_partitioned)

Checks if the elements of this iterator are partitioned according to the given predicate, -such that all those that return true precede all those that return false. Read more

1.27.0 · source

fn try_fold<B, F, R>(&mut self, init: B, f: F) -> Rwhere
 Self: Sized,
 F: FnMut(B, Self::Item) -> R,
 R: Try<Output = B>,

An iterator method that applies a function as long as it returns -successfully, producing a single, final value. Read more

1.27.0 · source

fn try_for_each<F, R>(&mut self, f: F) -> Rwhere
 Self: Sized,
 F: FnMut(Self::Item) -> R,
 R: Try<Output = ()>,

An iterator method that applies a fallible function to each item in the -iterator, stopping at the first error and returning that error. Read more

1.0.0 · source

fn fold<B, F>(self, init: B, f: F) -> Bwhere
Self: Sized,
F: FnMut(B, Self::Item) -> B,

Folds every element into an accumulator by applying an operation, -returning the final result. Read more

1.51.0 · source

fn reduce<F>(self, f: F) -> Option<Self::Item>where
Self: Sized,
F: FnMut(Self::Item, Self::Item) -> Self::Item,

Reduces the elements to a single one, by repeatedly applying a reducing -operation. Read more

source

fn try_reduce<F, R>(
 &mut self,
 f: F
) -> <<R as Try>::Residual as Residual<Option<<R as Try>::Output>>>::TryTypewhere
 Self: Sized,
 F: FnMut(Self::Item, Self::Item) -> R,
 R: Try<Output = Self::Item>,
 <R as Try>::Residual: Residual<Option<Self::Item>>,

🔬This is a nightly-only experimental API. (iterator_try_reduce)

Reduces the elements to a single one by repeatedly applying a reducing operation. If the -closure returns a failure, the failure is propagated back to the caller immediately. Read more

1.0.0 · source

fn all<F>(&mut self, f: F) -> boolwhere
Self: Sized,
F: FnMut(Self::Item) -> bool,

Tests if every element of the iterator matches a predicate. Read more

1.0.0 · source

fn any<F>(&mut self, f: F) -> boolwhere
Self: Sized,
F: FnMut(Self::Item) -> bool,

Tests if any element of the iterator matches a predicate. Read more

1.0.0 · source

fn find(&mut self, predicate: P) -> Option<Self::Item>where
Self: Sized,
P: FnMut(&Self::Item) -> bool,

Searches for an element of an iterator that satisfies a predicate. Read more

1.30.0 · source

fn find_map<B, F>(&mut self, f: F) -> Optionwhere
Self: Sized,
F: FnMut(Self::Item) -> Option,

Applies function to the elements of iterator and returns -the first non-none result. Read more

source

fn try_find<F, R>(
 &mut self,
 f: F
) -> <<R as Try>::Residual as Residual<Option<Self::Item>>>::TryTypewhere
 Self: Sized,
 F: FnMut(&Self::Item) -> R,
 R: Try<Output = bool>,
 <R as Try>::Residual: Residual<Option<Self::Item>>,

🔬This is a nightly-only experimental API. (try_find)

Applies function to the elements of iterator and returns -the first true result or the first error. Read more

1.0.0 · source

fn position(&mut self, predicate: P) -> Option<usize>where
Self: Sized,
P: FnMut(Self::Item) -> bool,

Searches for an element in an iterator, returning its index. Read more

1.6.0 · source

fn max_by_key<B, F>(self, f: F) -> Option<Self::Item>where
 B: Ord,
 Self: Sized,
 F: FnMut(&Self::Item) -> B,

Returns the element that gives the maximum value from the -specified function. Read more

1.15.0 · source

fn max_by<F>(self, compare: F) -> Option<Self::Item>where
Self: Sized,
F: FnMut(&Self::Item, &Self::Item) -> Ordering,

Returns the element that gives the maximum value with respect to the -specified comparison function. Read more

1.6.0 · source

fn min_by_key<B, F>(self, f: F) -> Option<Self::Item>where
 B: Ord,
 Self: Sized,
 F: FnMut(&Self::Item) -> B,

Returns the element that gives the minimum value from the -specified function. Read more

1.15.0 · source

fn min_by<F>(self, compare: F) -> Option<Self::Item>where
Self: Sized,
F: FnMut(&Self::Item, &Self::Item) -> Ordering,

Returns the element that gives the minimum value with respect to the -specified comparison function. Read more

1.0.0 · source

fn unzip<A, B, FromA, FromB>(self) -> (FromA, FromB)where
 FromA: Default + Extend<A>,
 FromB: Default + Extend,
 Self: Sized + Iterator<Item = (A, B)>,

Converts an iterator of pairs into a pair of containers. Read more

1.36.0 · source

fn copied<'a, T>(self) -> Copied<Self>where
T: 'a + Copy,
Self: Sized + Iterator<Item = &'a T>,

Creates an iterator which copies all of its elements. Read more

1.0.0 · source

fn cloned<'a, T>(self) -> Cloned<Self>where
T: 'a + Clone,
Self: Sized + Iterator<Item = &'a T>,

Creates an iterator which clones all of its elements. Read more

1.0.0 · source

fn cycle(self) -> Cycle<Self>where
Self: Sized + Clone,

Repeats an iterator endlessly. Read more

source

fn array_chunks<const N: usize>(self) -> ArrayChunks<Self, N>where
Self: Sized,

🔬This is a nightly-only experimental API. (iter_array_chunks)

Returns an iterator over N elements of the iterator at a time. Read more

1.11.0 · source

fn sum<S>(self) -> Swhere
Self: Sized,
S: Sum<Self::Item>,

Sums the elements of an iterator. Read more

1.11.0 · source

fn product(self) -> Pwhere
Self: Sized,
P: Product<Self::Item>,

Iterates over the entire iterator, multiplying all the elements Read more

source

fn cmp_by<I, F>(self, other: I, cmp: F) -> Orderingwhere
 Self: Sized,
 I: IntoIterator,
 F: FnMut(Self::Item, ::Item) -> Ordering,

🔬This is a nightly-only experimental API. (iter_order_by)

Lexicographically compares the elements of this Iterator with those -of another with respect to the specified comparison function. Read more

1.5.0 · source

fn partial_cmp(self, other: I) -> Option<Ordering>where
 I: IntoIterator,
 Self::Item: PartialOrd<::Item>,
 Self: Sized,

Lexicographically compares the elements of this Iterator with those -of another. Read more

source

fn partial_cmp_by<I, F>(self, other: I, partial_cmp: F) -> Option<Ordering>where
 Self: Sized,
 I: IntoIterator,
 F: FnMut(Self::Item, ::Item) -> Option<Ordering>,

🔬This is a nightly-only experimental API. (iter_order_by)

Lexicographically compares the elements of this Iterator with those -of another with respect to the specified comparison function. Read more

1.5.0 · source

fn eq(self, other: I) -> boolwhere
 I: IntoIterator,
 Self::Item: PartialEq<::Item>,
 Self: Sized,

Determines if the elements of this Iterator are equal to those of -another. Read more

source

fn eq_by<I, F>(self, other: I, eq: F) -> boolwhere
 Self: Sized,
 I: IntoIterator,
 F: FnMut(Self::Item, ::Item) -> bool,

🔬This is a nightly-only experimental API. (iter_order_by)

Determines if the elements of this Iterator are equal to those of -another with respect to the specified equality function. Read more

1.5.0 · source

fn ne(self, other: I) -> boolwhere
 I: IntoIterator,
 Self::Item: PartialEq<::Item>,
 Self: Sized,

Determines if the elements of this Iterator are unequal to those of -another. Read more

1.5.0 · source

fn lt(self, other: I) -> boolwhere
 I: IntoIterator,
 Self::Item: PartialOrd<::Item>,
 Self: Sized,

Determines if the elements of this Iterator are lexicographically -less than those of another. Read more

1.5.0 · source

fn le(self, other: I) -> boolwhere
 I: IntoIterator,
 Self::Item: PartialOrd<::Item>,
 Self: Sized,

Determines if the elements of this Iterator are lexicographically -less or equal to those of another. Read more

1.5.0 · source

fn gt(self, other: I) -> boolwhere
 I: IntoIterator,
 Self::Item: PartialOrd<::Item>,
 Self: Sized,

Determines if the elements of this Iterator are lexicographically -greater than those of another. Read more

1.5.0 · source

fn ge(self, other: I) -> boolwhere
 I: IntoIterator,
 Self::Item: PartialOrd<::Item>,
 Self: Sized,

Determines if the elements of this Iterator are lexicographically -greater than or equal to those of another. Read more

source

fn is_sorted_by<F>(self, compare: F) -> boolwhere
Self: Sized,
F: FnMut(&Self::Item, &Self::Item) -> Option<Ordering>,

🔬This is a nightly-only experimental API. (is_sorted)

Checks if the elements of this iterator are sorted using the given comparator function. Read more

source

fn is_sorted_by_key<F, K>(self, f: F) -> boolwhere
 Self: Sized,
 F: FnMut(Self::Item) -> K,
 K: PartialOrd<K>,

🔬This is a nightly-only experimental API. (is_sorted)

Checks if the elements of this iterator are sorted using the given key extraction -function. Read more

Auto Trait Implementations

impl RefUnwindSafe for IndexVecIntoIter

impl Send for IndexVecIntoIter

impl Sync for IndexVecIntoIter

impl Unpin for IndexVecIntoIter

impl UnwindSafe for IndexVecIntoIter

Blanket Implementations

source

impl<T> Any for Twhere
T: 'static + ?Sized,

source

fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more

source

impl<T> Borrow<T> for Twhere
T: ?Sized,

const: unstable · source

fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more

source

impl<T> BorrowMut<T> for Twhere
T: ?Sized,

const: unstable · source

fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more

source

impl<T> From<T> for T

const: unstable · source

fn from(t: T) -> T

Returns the argument unchanged.

source

impl<T, U> Into for Twhere
U: From<T>,

const: unstable · source

fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of -From<T> for U chooses to do.

source

impl IntoIterator for Iwhere
I: Iterator,

type Item = ::Item

The type of the elements being iterated over.

type IntoIter = I

Which kind of iterator are we turning this into?

const: unstable · source

fn into_iter(self) -> I

Creates an iterator from a value. Read more

source

impl IteratorRandom for Iwhere
I: Iterator,

source

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

Choose one element at random from the iterator. Read more

source

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

Choose one element at random from the iterator. Read more

source

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

Collects values at random from the iterator into a supplied buffer -until that buffer is filled. Read more

source

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

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

source

impl<T> ToOwned for Twhere
T: Clone,

type Owned = T

The resulting type after obtaining ownership.

source

fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more

source

fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more

source

impl<T, U> TryFrom for Twhere
U: Into<T>,

type Error = Infallible

The type returned in the event of a conversion error.

const: unstable · source

fn try_from(value: U) -> Result<T, <T as TryFrom>::Error>

Performs the conversion.

source

impl<T, U> TryInto for Twhere
U: TryFrom<T>,

type Error = >::Error

The type returned in the event of a conversion error.

const: unstable · source

fn try_into(self) -> Result<U, >::Error>

Performs the conversion.

source

impl<V, T> VZip<V> for Twhere
V: MultiLane<T>,

source

fn vzip(self) -> V

Enum rand::seq::index::IndexVecIter

source · [−]

pub enum IndexVecIter<'a> {
-    // some variants omitted
-}

Expand description

Return type of IndexVec::iter.

Trait Implementations

source

impl<'a> Debug for IndexVecIter<'a>

source

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter. Read more

source

impl<'a> ExactSizeIterator for IndexVecIter<'a>

1.0.0 · source

fn len(&self) -> usize

Returns the exact remaining length of the iterator. Read more

source

fn is_empty(&self) -> bool

🔬This is a nightly-only experimental API. (exact_size_is_empty)

Returns true if the iterator is empty. Read more

source

impl<'a> Iterator for IndexVecIter<'a>

type Item = usize

The type of the elements being iterated over.

source

fn next(&mut self) -> Option<usize>

Advances the iterator and returns the next value. Read more

source

fn size_hint(&self) -> (usize, Option<usize>)

Returns the bounds on the remaining length of the iterator. Read more

source

fn next_chunk<const N: usize>(
&mut self
) -> Result<[Self::Item; N], IntoIter<Self::Item, N>>where
Self: Sized,

🔬This is a nightly-only experimental API. (iter_next_chunk)

Advances the iterator and returns an array containing the next N values. Read more

1.0.0 · source

fn count(self) -> usizewhere
Self: Sized,

Consumes the iterator, counting the number of iterations and returning it. Read more

1.0.0 · source

fn last(self) -> Option<Self::Item>where
Self: Sized,

Consumes the iterator, returning the last element. Read more

source

fn advance_by(&mut self, n: usize) -> Result<(), usize>

🔬This is a nightly-only experimental API. (iter_advance_by)

Advances the iterator by n elements. Read more

1.0.0 · source

fn nth(&mut self, n: usize) -> Option<Self::Item>

Returns the nth element of the iterator. Read more

1.28.0 · source

fn step_by(self, step: usize) -> StepBy<Self>where
Self: Sized,

Creates an iterator starting at the same point, but stepping by -the given amount at each iteration. Read more

1.0.0 · source

fn chain(self, other: U) -> Chain<Self, ::IntoIter>where
Self: Sized,
U: IntoIterator<Item = Self::Item>,

Takes two iterators and creates a new iterator over both in sequence. Read more

1.0.0 · source

fn zip(self, other: U) -> Zip<Self, ::IntoIter>where
Self: Sized,
U: IntoIterator,

‘Zips up’ two iterators into a single iterator of pairs. Read more

source

fn intersperse_with<G>(self, separator: G) -> IntersperseWith<Self, G>where
Self: Sized,
G: FnMut() -> Self::Item,

🔬This is a nightly-only experimental API. (iter_intersperse)

Creates a new iterator which places an item generated by separator -between adjacent items of the original iterator. Read more

1.0.0 · source

fn map<B, F>(self, f: F) -> Map<Self, F>where
Self: Sized,
F: FnMut(Self::Item) -> B,

Takes a closure and creates an iterator which calls that closure on each -element. Read more

1.21.0 · source

fn for_each<F>(self, f: F)where
Self: Sized,
F: FnMut(Self::Item),

Calls a closure on each element of an iterator. Read more

1.0.0 · source

fn filter(self, predicate: P) -> Filter<Self, P>where
Self: Sized,
P: FnMut(&Self::Item) -> bool,

Creates an iterator which uses a closure to determine if an element -should be yielded. Read more

1.0.0 · source

fn filter_map<B, F>(self, f: F) -> FilterMap<Self, F>where
Self: Sized,
F: FnMut(Self::Item) -> Option,

Creates an iterator that both filters and maps. Read more

1.0.0 · source

fn enumerate(self) -> Enumerate<Self>where
Self: Sized,

Creates an iterator which gives the current iteration count as well as -the next value. Read more

1.0.0 · source

fn peekable(self) -> Peekable<Self>where
Self: Sized,

Creates an iterator which can use the peek and peek_mut methods -to look at the next element of the iterator without consuming it. See -their documentation for more information. Read more

1.0.0 · source

fn skip_while(self, predicate: P) -> SkipWhile<Self, P>where
Self: Sized,
P: FnMut(&Self::Item) -> bool,

Creates an iterator that skips elements based on a predicate. Read more

1.0.0 · source

fn take_while(self, predicate: P) -> TakeWhile<Self, P>where
Self: Sized,
P: FnMut(&Self::Item) -> bool,

Creates an iterator that yields elements based on a predicate. Read more

1.57.0 · source

fn map_while<B, P>(self, predicate: P) -> MapWhile<Self, P>where
Self: Sized,
P: FnMut(Self::Item) -> Option,

Creates an iterator that both yields elements based on a predicate and maps. Read more

1.0.0 · source

fn skip(self, n: usize) -> Skip<Self>where
Self: Sized,

Creates an iterator that skips the first n elements. Read more

1.0.0 · source

fn take(self, n: usize) -> Take<Self>where
Self: Sized,

Creates an iterator that yields the first n elements, or fewer -if the underlying iterator ends sooner. Read more

1.0.0 · source

fn scan<St, B, F>(self, initial_state: St, f: F) -> Scan<Self, St, F>where
Self: Sized,
F: FnMut(&mut St, Self::Item) -> Option,

An iterator adapter similar to fold that holds internal state and -produces a new iterator. Read more

1.0.0 · source

fn flat_map<U, F>(self, f: F) -> FlatMap<Self, U, F>where
 Self: Sized,
 U: IntoIterator,
 F: FnMut(Self::Item) -> U,

Creates an iterator that works like map, but flattens nested structure. Read more

1.0.0 · source

fn fuse(self) -> Fuse<Self>where
Self: Sized,

Creates an iterator which ends after the first None. Read more

1.0.0 · source

fn inspect<F>(self, f: F) -> Inspect<Self, F>where
Self: Sized,
F: FnMut(&Self::Item),

Does something with each element of an iterator, passing the value on. Read more

1.0.0 · source

fn by_ref(&mut self) -> &mut Selfwhere
Self: Sized,

Borrows an iterator, rather than consuming it. Read more

1.0.0 · source

fn collect(self) -> Bwhere
B: FromIterator<Self::Item>,
Self: Sized,

Transforms an iterator into a collection. Read more

source

fn collect_into<E>(self, collection: &mut E) -> &mut Ewhere
E: Extend<Self::Item>,
Self: Sized,

🔬This is a nightly-only experimental API. (iter_collect_into)

Collects all the items from an iterator into a collection. Read more

1.0.0 · source

fn partition<B, F>(self, f: F) -> (B, B)where
 Self: Sized,
 B: Default + Extend<Self::Item>,
 F: FnMut(&Self::Item) -> bool,

Consumes an iterator, creating two collections from it. Read more

source

fn is_partitioned(self, predicate: P) -> boolwhere
Self: Sized,
P: FnMut(Self::Item) -> bool,

🔬This is a nightly-only experimental API. (iter_is_partitioned)

Checks if the elements of this iterator are partitioned according to the given predicate, -such that all those that return true precede all those that return false. Read more

1.27.0 · source

fn try_fold<B, F, R>(&mut self, init: B, f: F) -> Rwhere
 Self: Sized,
 F: FnMut(B, Self::Item) -> R,
 R: Try<Output = B>,

An iterator method that applies a function as long as it returns -successfully, producing a single, final value. Read more

1.27.0 · source

fn try_for_each<F, R>(&mut self, f: F) -> Rwhere
 Self: Sized,
 F: FnMut(Self::Item) -> R,
 R: Try<Output = ()>,

An iterator method that applies a fallible function to each item in the -iterator, stopping at the first error and returning that error. Read more

1.0.0 · source

fn fold<B, F>(self, init: B, f: F) -> Bwhere
Self: Sized,
F: FnMut(B, Self::Item) -> B,

Folds every element into an accumulator by applying an operation, -returning the final result. Read more

1.51.0 · source

fn reduce<F>(self, f: F) -> Option<Self::Item>where
Self: Sized,
F: FnMut(Self::Item, Self::Item) -> Self::Item,

Reduces the elements to a single one, by repeatedly applying a reducing -operation. Read more

source

fn try_reduce<F, R>(
 &mut self,
 f: F
) -> <<R as Try>::Residual as Residual<Option<<R as Try>::Output>>>::TryTypewhere
 Self: Sized,
 F: FnMut(Self::Item, Self::Item) -> R,
 R: Try<Output = Self::Item>,
 <R as Try>::Residual: Residual<Option<Self::Item>>,

🔬This is a nightly-only experimental API. (iterator_try_reduce)

Reduces the elements to a single one by repeatedly applying a reducing operation. If the -closure returns a failure, the failure is propagated back to the caller immediately. Read more

1.0.0 · source

fn all<F>(&mut self, f: F) -> boolwhere
Self: Sized,
F: FnMut(Self::Item) -> bool,

Tests if every element of the iterator matches a predicate. Read more

1.0.0 · source

fn any<F>(&mut self, f: F) -> boolwhere
Self: Sized,
F: FnMut(Self::Item) -> bool,

Tests if any element of the iterator matches a predicate. Read more

1.0.0 · source

fn find(&mut self, predicate: P) -> Option<Self::Item>where
Self: Sized,
P: FnMut(&Self::Item) -> bool,

Searches for an element of an iterator that satisfies a predicate. Read more

1.30.0 · source

fn find_map<B, F>(&mut self, f: F) -> Optionwhere
Self: Sized,
F: FnMut(Self::Item) -> Option,

Applies function to the elements of iterator and returns -the first non-none result. Read more

source

fn try_find<F, R>(
 &mut self,
 f: F
) -> <<R as Try>::Residual as Residual<Option<Self::Item>>>::TryTypewhere
 Self: Sized,
 F: FnMut(&Self::Item) -> R,
 R: Try<Output = bool>,
 <R as Try>::Residual: Residual<Option<Self::Item>>,

🔬This is a nightly-only experimental API. (try_find)

Applies function to the elements of iterator and returns -the first true result or the first error. Read more

1.0.0 · source

fn position(&mut self, predicate: P) -> Option<usize>where
Self: Sized,
P: FnMut(Self::Item) -> bool,

Searches for an element in an iterator, returning its index. Read more

1.6.0 · source

fn max_by_key<B, F>(self, f: F) -> Option<Self::Item>where
 B: Ord,
 Self: Sized,
 F: FnMut(&Self::Item) -> B,

Returns the element that gives the maximum value from the -specified function. Read more

1.15.0 · source

fn max_by<F>(self, compare: F) -> Option<Self::Item>where
Self: Sized,
F: FnMut(&Self::Item, &Self::Item) -> Ordering,

Returns the element that gives the maximum value with respect to the -specified comparison function. Read more

1.6.0 · source

fn min_by_key<B, F>(self, f: F) -> Option<Self::Item>where
 B: Ord,
 Self: Sized,
 F: FnMut(&Self::Item) -> B,

Returns the element that gives the minimum value from the -specified function. Read more

1.15.0 · source

fn min_by<F>(self, compare: F) -> Option<Self::Item>where
Self: Sized,
F: FnMut(&Self::Item, &Self::Item) -> Ordering,

Returns the element that gives the minimum value with respect to the -specified comparison function. Read more

1.0.0 · source

fn unzip<A, B, FromA, FromB>(self) -> (FromA, FromB)where
 FromA: Default + Extend<A>,
 FromB: Default + Extend,
 Self: Sized + Iterator<Item = (A, B)>,

Converts an iterator of pairs into a pair of containers. Read more

1.36.0 · source

fn copied<'a, T>(self) -> Copied<Self>where
T: 'a + Copy,
Self: Sized + Iterator<Item = &'a T>,

Creates an iterator which copies all of its elements. Read more

1.0.0 · source

fn cloned<'a, T>(self) -> Cloned<Self>where
T: 'a + Clone,
Self: Sized + Iterator<Item = &'a T>,

Creates an iterator which clones all of its elements. Read more

source

fn array_chunks<const N: usize>(self) -> ArrayChunks<Self, N>where
Self: Sized,

🔬This is a nightly-only experimental API. (iter_array_chunks)

Returns an iterator over N elements of the iterator at a time. Read more

1.11.0 · source

fn sum<S>(self) -> Swhere
Self: Sized,
S: Sum<Self::Item>,

Sums the elements of an iterator. Read more

1.11.0 · source

fn product(self) -> Pwhere
Self: Sized,
P: Product<Self::Item>,

Iterates over the entire iterator, multiplying all the elements Read more

source

fn cmp_by<I, F>(self, other: I, cmp: F) -> Orderingwhere
 Self: Sized,
 I: IntoIterator,
 F: FnMut(Self::Item, ::Item) -> Ordering,

🔬This is a nightly-only experimental API. (iter_order_by)

Lexicographically compares the elements of this Iterator with those -of another with respect to the specified comparison function. Read more

1.5.0 · source

fn partial_cmp(self, other: I) -> Option<Ordering>where
 I: IntoIterator,
 Self::Item: PartialOrd<::Item>,
 Self: Sized,

Lexicographically compares the elements of this Iterator with those -of another. Read more

source

fn partial_cmp_by<I, F>(self, other: I, partial_cmp: F) -> Option<Ordering>where
 Self: Sized,
 I: IntoIterator,
 F: FnMut(Self::Item, ::Item) -> Option<Ordering>,

🔬This is a nightly-only experimental API. (iter_order_by)

Lexicographically compares the elements of this Iterator with those -of another with respect to the specified comparison function. Read more

1.5.0 · source

fn eq(self, other: I) -> boolwhere
 I: IntoIterator,
 Self::Item: PartialEq<::Item>,
 Self: Sized,

Determines if the elements of this Iterator are equal to those of -another. Read more

source

fn eq_by<I, F>(self, other: I, eq: F) -> boolwhere
 Self: Sized,
 I: IntoIterator,
 F: FnMut(Self::Item, ::Item) -> bool,

🔬This is a nightly-only experimental API. (iter_order_by)

Determines if the elements of this Iterator are equal to those of -another with respect to the specified equality function. Read more

1.5.0 · source

fn ne(self, other: I) -> boolwhere
 I: IntoIterator,
 Self::Item: PartialEq<::Item>,
 Self: Sized,

Determines if the elements of this Iterator are unequal to those of -another. Read more

1.5.0 · source

fn lt(self, other: I) -> boolwhere
 I: IntoIterator,
 Self::Item: PartialOrd<::Item>,
 Self: Sized,

Determines if the elements of this Iterator are lexicographically -less than those of another. Read more

1.5.0 · source

fn le(self, other: I) -> boolwhere
 I: IntoIterator,
 Self::Item: PartialOrd<::Item>,
 Self: Sized,

Determines if the elements of this Iterator are lexicographically -less or equal to those of another. Read more

1.5.0 · source

fn gt(self, other: I) -> boolwhere
 I: IntoIterator,
 Self::Item: PartialOrd<::Item>,
 Self: Sized,

Determines if the elements of this Iterator are lexicographically -greater than those of another. Read more

1.5.0 · source

fn ge(self, other: I) -> boolwhere
 I: IntoIterator,
 Self::Item: PartialOrd<::Item>,
 Self: Sized,

Determines if the elements of this Iterator are lexicographically -greater than or equal to those of another. Read more

source

fn is_sorted_by<F>(self, compare: F) -> boolwhere
Self: Sized,
F: FnMut(&Self::Item, &Self::Item) -> Option<Ordering>,

🔬This is a nightly-only experimental API. (is_sorted)

Checks if the elements of this iterator are sorted using the given comparator function. Read more

source

fn is_sorted_by_key<F, K>(self, f: F) -> boolwhere
 Self: Sized,
 F: FnMut(Self::Item) -> K,
 K: PartialOrd<K>,

🔬This is a nightly-only experimental API. (is_sorted)

Checks if the elements of this iterator are sorted using the given key extraction -function. Read more

Auto Trait Implementations

impl<'a> RefUnwindSafe for IndexVecIter<'a>

impl<'a> Send for IndexVecIter<'a>

impl<'a> Sync for IndexVecIter<'a>

impl<'a> Unpin for IndexVecIter<'a>

impl<'a> UnwindSafe for IndexVecIter<'a>

Blanket Implementations

source

impl<T> Any for Twhere
T: 'static + ?Sized,

source

fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more

source

impl<T> Borrow<T> for Twhere
T: ?Sized,

const: unstable · source

fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more

source

impl<T> BorrowMut<T> for Twhere
T: ?Sized,

const: unstable · source

fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more

source

impl<T> From<T> for T

const: unstable · source

fn from(t: T) -> T

Returns the argument unchanged.

source

impl<T, U> Into for Twhere
U: From<T>,

const: unstable · source

fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of -From<T> for U chooses to do.

source

impl IntoIterator for Iwhere
I: Iterator,

type Item = ::Item

The type of the elements being iterated over.

type IntoIter = I

Which kind of iterator are we turning this into?

const: unstable · source

fn into_iter(self) -> I

Creates an iterator from a value. Read more

source

impl IteratorRandom for Iwhere
I: Iterator,

source

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

Choose one element at random from the iterator. Read more

source

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

Choose one element at random from the iterator. Read more

source

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

Collects values at random from the iterator into a supplied buffer -until that buffer is filled. Read more

source

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

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

source

impl<T, U> TryFrom for Twhere
U: Into<T>,

type Error = Infallible

The type returned in the event of a conversion error.

const: unstable · source

fn try_from(value: U) -> Result<T, <T as TryFrom>::Error>

Performs the conversion.

source

impl<T, U> TryInto for Twhere
U: TryFrom<T>,

type Error = >::Error

The type returned in the event of a conversion error.

const: unstable · source

fn try_into(self) -> Result<U, >::Error>

Performs the conversion.

source

impl<V, T> VZip<V> for Twhere
V: MultiLane<T>,

source

fn vzip(self) -> V

Function rand::seq::index::sample

source · [−]

pub fn sample<R>(rng: &mut R, length: usize, amount: usize) -> IndexVecwhere
    R: Rng + ?Sized,

Expand description

Randomly sample exactly amount distinct indices from 0..length, and -return them in random order (fully shuffled).

This method is used internally by the slice sampling methods, but it can -sometimes be useful to have the indices themselves so this is provided as -an alternative.

The implementation used is not specified; we automatically select the -fastest available algorithm for the length and amount parameters -(based on detailed profiling on an Intel Haswell CPU). Roughly speaking, -complexity is O(amount), except that when amount is small, performance -is closer to O(amount^2), and when length is close to amount then -O(length).

Note that performance is significantly better over u32 indices than over -u64 indices. Because of this we hide the underlying type behind an -abstraction, IndexVec.

If an allocation-free no_std function is required, it is suggested -to adapt the internal sample_floyd implementation.

Panics if amount > length.

Function rand::seq::index::sample_weighted

source · [−]

pub fn sample_weighted<R, F, X>(
    rng: &mut R,
    length: usize,
    weight: F,
    amount: usize
) -> Result<IndexVec, WeightedError>where
    R: Rng + ?Sized,
    F: Fn(usize) -> X,
    X: Into<f64>,

Expand description

Randomly sample exactly amount distinct indices from 0..length, and -return them in an arbitrary order (there is no guarantee of shuffling or -ordering). The weights are to be provided by the input function weights, -which will be called once for each index.

This method is used internally by the slice sampling methods, but it can -sometimes be useful to have the indices themselves so this is provided as -an alternative.

This implementation uses O(length + amount) space and O(length) time -if the “nightly” feature is enabled, or O(length) space and -O(length + amount * log length) time otherwise.

Panics if amount > length.

Module rand::seq::index

source · [−]

Expand description

Low-level API for sampling indices

Enums

IndexVec

A vector of indices.

IndexVecIntoIter

Return type of IndexVec::into_iter.

IndexVecIter

Return type of IndexVec::iter.

Functions

sample

Randomly sample exactly amount distinct indices from 0..length, and -return them in random order (fully shuffled).

sample_weighted

Struct rand::seq::SliceChooseIter

source · [−]

pub struct SliceChooseIter<'a, S: ?Sized + 'a, T: 'a> { /* private fields */ }

Expand description

An iterator over multiple slice elements.

This struct is created by -SliceRandom::choose_multiple.

Trait Implementations

source

impl<'a, S: Debug + ?Sized + 'a, T: Debug + 'a> Debug for SliceChooseIter<'a, S, T>

source

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter. Read more

source

impl<'a, S: Index<usize, Output = T> + ?Sized + 'a, T: 'a> ExactSizeIterator for SliceChooseIter<'a, S, T>

source

fn len(&self) -> usize

Returns the exact remaining length of the iterator. Read more

source

fn is_empty(&self) -> bool

🔬This is a nightly-only experimental API. (exact_size_is_empty)

Returns true if the iterator is empty. Read more

source

impl<'a, S: Index<usize, Output = T> + ?Sized + 'a, T: 'a> Iterator for SliceChooseIter<'a, S, T>

type Item = &'a T

The type of the elements being iterated over.

source

fn next(&mut self) -> Option<Self::Item>

Advances the iterator and returns the next value. Read more

source

fn size_hint(&self) -> (usize, Option<usize>)

Returns the bounds on the remaining length of the iterator. Read more

source

fn next_chunk<const N: usize>(
&mut self
) -> Result<[Self::Item; N], IntoIter<Self::Item, N>>where
Self: Sized,

🔬This is a nightly-only experimental API. (iter_next_chunk)

Advances the iterator and returns an array containing the next N values. Read more

1.0.0 · source

fn count(self) -> usizewhere
Self: Sized,

Consumes the iterator, counting the number of iterations and returning it. Read more

1.0.0 · source

fn last(self) -> Option<Self::Item>where
Self: Sized,

Consumes the iterator, returning the last element. Read more

source

fn advance_by(&mut self, n: usize) -> Result<(), usize>

🔬This is a nightly-only experimental API. (iter_advance_by)

Advances the iterator by n elements. Read more

1.0.0 · source

fn nth(&mut self, n: usize) -> Option<Self::Item>

Returns the nth element of the iterator. Read more

1.28.0 · source

fn step_by(self, step: usize) -> StepBy<Self>where
Self: Sized,

Creates an iterator starting at the same point, but stepping by -the given amount at each iteration. Read more

1.0.0 · source

fn chain(self, other: U) -> Chain<Self, ::IntoIter>where
Self: Sized,
U: IntoIterator<Item = Self::Item>,

Takes two iterators and creates a new iterator over both in sequence. Read more

1.0.0 · source

fn zip(self, other: U) -> Zip<Self, ::IntoIter>where
Self: Sized,
U: IntoIterator,

‘Zips up’ two iterators into a single iterator of pairs. Read more

source

fn intersperse_with<G>(self, separator: G) -> IntersperseWith<Self, G>where
Self: Sized,
G: FnMut() -> Self::Item,

🔬This is a nightly-only experimental API. (iter_intersperse)

Creates a new iterator which places an item generated by separator -between adjacent items of the original iterator. Read more

1.0.0 · source

fn map<B, F>(self, f: F) -> Map<Self, F>where
Self: Sized,
F: FnMut(Self::Item) -> B,

Takes a closure and creates an iterator which calls that closure on each -element. Read more

1.21.0 · source

fn for_each<F>(self, f: F)where
Self: Sized,
F: FnMut(Self::Item),

Calls a closure on each element of an iterator. Read more

1.0.0 · source

fn filter(self, predicate: P) -> Filter<Self, P>where
Self: Sized,
P: FnMut(&Self::Item) -> bool,

Creates an iterator which uses a closure to determine if an element -should be yielded. Read more

1.0.0 · source

fn filter_map<B, F>(self, f: F) -> FilterMap<Self, F>where
Self: Sized,
F: FnMut(Self::Item) -> Option,

Creates an iterator that both filters and maps. Read more

1.0.0 · source

fn enumerate(self) -> Enumerate<Self>where
Self: Sized,

Creates an iterator which gives the current iteration count as well as -the next value. Read more

1.0.0 · source

fn peekable(self) -> Peekable<Self>where
Self: Sized,

Creates an iterator which can use the peek and peek_mut methods -to look at the next element of the iterator without consuming it. See -their documentation for more information. Read more

1.0.0 · source

fn skip_while(self, predicate: P) -> SkipWhile<Self, P>where
Self: Sized,
P: FnMut(&Self::Item) -> bool,

Creates an iterator that skips elements based on a predicate. Read more

1.0.0 · source

fn take_while(self, predicate: P) -> TakeWhile<Self, P>where
Self: Sized,
P: FnMut(&Self::Item) -> bool,

Creates an iterator that yields elements based on a predicate. Read more

1.57.0 · source

fn map_while<B, P>(self, predicate: P) -> MapWhile<Self, P>where
Self: Sized,
P: FnMut(Self::Item) -> Option,

Creates an iterator that both yields elements based on a predicate and maps. Read more

1.0.0 · source

fn skip(self, n: usize) -> Skip<Self>where
Self: Sized,

Creates an iterator that skips the first n elements. Read more

1.0.0 · source

fn take(self, n: usize) -> Take<Self>where
Self: Sized,

Creates an iterator that yields the first n elements, or fewer -if the underlying iterator ends sooner. Read more

1.0.0 · source

fn scan<St, B, F>(self, initial_state: St, f: F) -> Scan<Self, St, F>where
Self: Sized,
F: FnMut(&mut St, Self::Item) -> Option,

An iterator adapter similar to fold that holds internal state and -produces a new iterator. Read more

1.0.0 · source

fn flat_map<U, F>(self, f: F) -> FlatMap<Self, U, F>where
 Self: Sized,
 U: IntoIterator,
 F: FnMut(Self::Item) -> U,

Creates an iterator that works like map, but flattens nested structure. Read more

1.0.0 · source

fn fuse(self) -> Fuse<Self>where
Self: Sized,

Creates an iterator which ends after the first None. Read more

1.0.0 · source

fn inspect<F>(self, f: F) -> Inspect<Self, F>where
Self: Sized,
F: FnMut(&Self::Item),

Does something with each element of an iterator, passing the value on. Read more

1.0.0 · source

fn by_ref(&mut self) -> &mut Selfwhere
Self: Sized,

Borrows an iterator, rather than consuming it. Read more

1.0.0 · source

fn collect(self) -> Bwhere
B: FromIterator<Self::Item>,
Self: Sized,

Transforms an iterator into a collection. Read more

source

fn collect_into<E>(self, collection: &mut E) -> &mut Ewhere
E: Extend<Self::Item>,
Self: Sized,

🔬This is a nightly-only experimental API. (iter_collect_into)

Collects all the items from an iterator into a collection. Read more

1.0.0 · source

fn partition<B, F>(self, f: F) -> (B, B)where
 Self: Sized,
 B: Default + Extend<Self::Item>,
 F: FnMut(&Self::Item) -> bool,

Consumes an iterator, creating two collections from it. Read more

source

fn is_partitioned(self, predicate: P) -> boolwhere
Self: Sized,
P: FnMut(Self::Item) -> bool,

🔬This is a nightly-only experimental API. (iter_is_partitioned)

Checks if the elements of this iterator are partitioned according to the given predicate, -such that all those that return true precede all those that return false. Read more

1.27.0 · source

fn try_fold<B, F, R>(&mut self, init: B, f: F) -> Rwhere
 Self: Sized,
 F: FnMut(B, Self::Item) -> R,
 R: Try<Output = B>,

An iterator method that applies a function as long as it returns -successfully, producing a single, final value. Read more

1.27.0 · source

fn try_for_each<F, R>(&mut self, f: F) -> Rwhere
 Self: Sized,
 F: FnMut(Self::Item) -> R,
 R: Try<Output = ()>,

An iterator method that applies a fallible function to each item in the -iterator, stopping at the first error and returning that error. Read more

1.0.0 · source

fn fold<B, F>(self, init: B, f: F) -> Bwhere
Self: Sized,
F: FnMut(B, Self::Item) -> B,

Folds every element into an accumulator by applying an operation, -returning the final result. Read more

1.51.0 · source

fn reduce<F>(self, f: F) -> Option<Self::Item>where
Self: Sized,
F: FnMut(Self::Item, Self::Item) -> Self::Item,

Reduces the elements to a single one, by repeatedly applying a reducing -operation. Read more

source

fn try_reduce<F, R>(
 &mut self,
 f: F
) -> <<R as Try>::Residual as Residual<Option<<R as Try>::Output>>>::TryTypewhere
 Self: Sized,
 F: FnMut(Self::Item, Self::Item) -> R,
 R: Try<Output = Self::Item>,
 <R as Try>::Residual: Residual<Option<Self::Item>>,

🔬This is a nightly-only experimental API. (iterator_try_reduce)

Reduces the elements to a single one by repeatedly applying a reducing operation. If the -closure returns a failure, the failure is propagated back to the caller immediately. Read more

1.0.0 · source

fn all<F>(&mut self, f: F) -> boolwhere
Self: Sized,
F: FnMut(Self::Item) -> bool,

Tests if every element of the iterator matches a predicate. Read more

1.0.0 · source

fn any<F>(&mut self, f: F) -> boolwhere
Self: Sized,
F: FnMut(Self::Item) -> bool,

Tests if any element of the iterator matches a predicate. Read more

1.0.0 · source

fn find(&mut self, predicate: P) -> Option<Self::Item>where
Self: Sized,
P: FnMut(&Self::Item) -> bool,

Searches for an element of an iterator that satisfies a predicate. Read more

1.30.0 · source

fn find_map<B, F>(&mut self, f: F) -> Optionwhere
Self: Sized,
F: FnMut(Self::Item) -> Option,

Applies function to the elements of iterator and returns -the first non-none result. Read more

source

fn try_find<F, R>(
 &mut self,
 f: F
) -> <<R as Try>::Residual as Residual<Option<Self::Item>>>::TryTypewhere
 Self: Sized,
 F: FnMut(&Self::Item) -> R,
 R: Try<Output = bool>,
 <R as Try>::Residual: Residual<Option<Self::Item>>,

🔬This is a nightly-only experimental API. (try_find)

Applies function to the elements of iterator and returns -the first true result or the first error. Read more

1.0.0 · source

fn position(&mut self, predicate: P) -> Option<usize>where
Self: Sized,
P: FnMut(Self::Item) -> bool,

Searches for an element in an iterator, returning its index. Read more

1.6.0 · source

fn max_by_key<B, F>(self, f: F) -> Option<Self::Item>where
 B: Ord,
 Self: Sized,
 F: FnMut(&Self::Item) -> B,

Returns the element that gives the maximum value from the -specified function. Read more

1.15.0 · source

fn max_by<F>(self, compare: F) -> Option<Self::Item>where
Self: Sized,
F: FnMut(&Self::Item, &Self::Item) -> Ordering,

Returns the element that gives the maximum value with respect to the -specified comparison function. Read more

1.6.0 · source

fn min_by_key<B, F>(self, f: F) -> Option<Self::Item>where
 B: Ord,
 Self: Sized,
 F: FnMut(&Self::Item) -> B,

Returns the element that gives the minimum value from the -specified function. Read more

1.15.0 · source

fn min_by<F>(self, compare: F) -> Option<Self::Item>where
Self: Sized,
F: FnMut(&Self::Item, &Self::Item) -> Ordering,

Returns the element that gives the minimum value with respect to the -specified comparison function. Read more

1.0.0 · source

fn unzip<A, B, FromA, FromB>(self) -> (FromA, FromB)where
 FromA: Default + Extend<A>,
 FromB: Default + Extend,
 Self: Sized + Iterator<Item = (A, B)>,

Converts an iterator of pairs into a pair of containers. Read more

1.36.0 · source

fn copied<'a, T>(self) -> Copied<Self>where
T: 'a + Copy,
Self: Sized + Iterator<Item = &'a T>,

Creates an iterator which copies all of its elements. Read more

1.0.0 · source

fn cloned<'a, T>(self) -> Cloned<Self>where
T: 'a + Clone,
Self: Sized + Iterator<Item = &'a T>,

Creates an iterator which clones all of its elements. Read more

source

fn array_chunks<const N: usize>(self) -> ArrayChunks<Self, N>where
Self: Sized,

🔬This is a nightly-only experimental API. (iter_array_chunks)

Returns an iterator over N elements of the iterator at a time. Read more

1.11.0 · source

fn sum<S>(self) -> Swhere
Self: Sized,
S: Sum<Self::Item>,

Sums the elements of an iterator. Read more

1.11.0 · source

fn product(self) -> Pwhere
Self: Sized,
P: Product<Self::Item>,

Iterates over the entire iterator, multiplying all the elements Read more

source

fn cmp_by<I, F>(self, other: I, cmp: F) -> Orderingwhere
 Self: Sized,
 I: IntoIterator,
 F: FnMut(Self::Item, ::Item) -> Ordering,

🔬This is a nightly-only experimental API. (iter_order_by)

Lexicographically compares the elements of this Iterator with those -of another with respect to the specified comparison function. Read more

1.5.0 · source

fn partial_cmp(self, other: I) -> Option<Ordering>where
 I: IntoIterator,
 Self::Item: PartialOrd<::Item>,
 Self: Sized,

Lexicographically compares the elements of this Iterator with those -of another. Read more

source

fn partial_cmp_by<I, F>(self, other: I, partial_cmp: F) -> Option<Ordering>where
 Self: Sized,
 I: IntoIterator,
 F: FnMut(Self::Item, ::Item) -> Option<Ordering>,

🔬This is a nightly-only experimental API. (iter_order_by)

Lexicographically compares the elements of this Iterator with those -of another with respect to the specified comparison function. Read more

1.5.0 · source

fn eq(self, other: I) -> boolwhere
 I: IntoIterator,
 Self::Item: PartialEq<::Item>,
 Self: Sized,

Determines if the elements of this Iterator are equal to those of -another. Read more

source

fn eq_by<I, F>(self, other: I, eq: F) -> boolwhere
 Self: Sized,
 I: IntoIterator,
 F: FnMut(Self::Item, ::Item) -> bool,

🔬This is a nightly-only experimental API. (iter_order_by)

Determines if the elements of this Iterator are equal to those of -another with respect to the specified equality function. Read more

1.5.0 · source

fn ne(self, other: I) -> boolwhere
 I: IntoIterator,
 Self::Item: PartialEq<::Item>,
 Self: Sized,

Determines if the elements of this Iterator are unequal to those of -another. Read more

1.5.0 · source

fn lt(self, other: I) -> boolwhere
 I: IntoIterator,
 Self::Item: PartialOrd<::Item>,
 Self: Sized,

Determines if the elements of this Iterator are lexicographically -less than those of another. Read more

1.5.0 · source

fn le(self, other: I) -> boolwhere
 I: IntoIterator,
 Self::Item: PartialOrd<::Item>,
 Self: Sized,

Determines if the elements of this Iterator are lexicographically -less or equal to those of another. Read more

1.5.0 · source

fn gt(self, other: I) -> boolwhere
 I: IntoIterator,
 Self::Item: PartialOrd<::Item>,
 Self: Sized,

Determines if the elements of this Iterator are lexicographically -greater than those of another. Read more

1.5.0 · source

fn ge(self, other: I) -> boolwhere
 I: IntoIterator,
 Self::Item: PartialOrd<::Item>,
 Self: Sized,

Determines if the elements of this Iterator are lexicographically -greater than or equal to those of another. Read more

source

fn is_sorted_by<F>(self, compare: F) -> boolwhere
Self: Sized,
F: FnMut(&Self::Item, &Self::Item) -> Option<Ordering>,

🔬This is a nightly-only experimental API. (is_sorted)

Checks if the elements of this iterator are sorted using the given comparator function. Read more

source

fn is_sorted_by_key<F, K>(self, f: F) -> boolwhere
 Self: Sized,
 F: FnMut(Self::Item) -> K,
 K: PartialOrd<K>,

🔬This is a nightly-only experimental API. (is_sorted)

Checks if the elements of this iterator are sorted using the given key extraction -function. Read more

Auto Trait Implementations

impl<'a, S: ?Sized, T> RefUnwindSafe for SliceChooseIter<'a, S, T>where
S: RefUnwindSafe,
T: RefUnwindSafe,

impl<'a, S: ?Sized, T> Send for SliceChooseIter<'a, S, T>where
S: Sync,
T: Send,

impl<'a, S: ?Sized, T> Sync for SliceChooseIter<'a, S, T>where
S: Sync,
T: Sync,

impl<'a, S: ?Sized, T> Unpin for SliceChooseIter<'a, S, T>where
T: Unpin,

impl<'a, S: ?Sized, T> UnwindSafe for SliceChooseIter<'a, S, T>where
S: RefUnwindSafe,
T: UnwindSafe,

Blanket Implementations

source

impl<T> Any for Twhere
T: 'static + ?Sized,

source

fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more

source

impl<T> Borrow<T> for Twhere
T: ?Sized,

const: unstable · source

fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more

source

impl<T> BorrowMut<T> for Twhere
T: ?Sized,

const: unstable · source

fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more

source

impl<T> From<T> for T

const: unstable · source

fn from(t: T) -> T

Returns the argument unchanged.

source

impl<T, U> Into for Twhere
U: From<T>,

const: unstable · source

fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of -From<T> for U chooses to do.

source

impl IntoIterator for Iwhere
I: Iterator,

type Item = ::Item

The type of the elements being iterated over.

type IntoIter = I

Which kind of iterator are we turning this into?

const: unstable · source

fn into_iter(self) -> I

Creates an iterator from a value. Read more

source

impl IteratorRandom for Iwhere
I: Iterator,

source

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

Choose one element at random from the iterator. Read more

source

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

Choose one element at random from the iterator. Read more

source

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

Collects values at random from the iterator into a supplied buffer -until that buffer is filled. Read more

source

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

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

source

impl<T, U> TryFrom for Twhere
U: Into<T>,

type Error = Infallible

The type returned in the event of a conversion error.

const: unstable · source

fn try_from(value: U) -> Result<T, <T as TryFrom>::Error>

Performs the conversion.

source

impl<T, U> TryInto for Twhere
U: TryFrom<T>,

type Error = >::Error

The type returned in the event of a conversion error.

const: unstable · source

fn try_into(self) -> Result<U, >::Error>

Performs the conversion.

source

impl<V, T> VZip<V> for Twhere
V: MultiLane<T>,

source

fn vzip(self) -> V

Trait rand::seq::IteratorRandom

source · [−]

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

Expand description

Extension trait on iterators, providing random sampling methods.

This trait is implemented on all iterators I where I: Iterator + Sized -and provides methods for -choosing one or more elements. You must use this trait:

- -

use rand::seq::IteratorRandom;
-
-let mut rng = rand::thread_rng();
-
-let faces = "😀😎😐😕😠😢";
-println!("I am {}!", faces.chars().choose(&mut rng).unwrap());

Example output (non-deterministic):

I am 😀!
-

Provided Methods

source

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

Choose one element at random from the iterator.

Returns None if and only if the iterator is empty.

This method uses Iterator::size_hint for optimisation. With an -accurate hint and where Iterator::nth is a constant-time operation -this method can offer O(1) performance. Where no size hint is -available, complexity is O(n) where n is the iterator length. -Partial hints (where lower > 0) also improve performance.

Note that the output values and the number of RNG samples used -depends on size hints. In particular, Iterator combinators that don’t -change the values yielded but change the size hints may result in -choose returning different elements. If you want consistent results -and RNG usage consider using IteratorRandom::choose_stable.

source

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

Choose one element at random from the iterator.

Returns None if and only if the iterator is empty.

This method is very similar to choose except that the result -only depends on the length of the iterator and the values produced by -rng. Notably for any iterator of a given length this will make the -same requests to rng and if the same sequence of values are produced -the same index will be selected from self. This may be useful if you -need consistent results no matter what type of iterator you are working -with. If you do not need this stability prefer choose.

Note that this method still uses Iterator::size_hint to skip -constructing elements where possible, however the selection and rng -calls are the same in the face of this optimization. If you want to -force every element to be created regardless call .inspect(|e| ()).

source

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

Collects values at random from the iterator into a supplied buffer -until that buffer is filled.

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 the length -of the buffer 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. -For slices, prefer SliceRandom::choose_multiple.

source

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

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. -For slices, prefer SliceRandom::choose_multiple.

Implementors

source

impl IteratorRandom for Iwhere
I: Iterator + Sized,

Trait rand::seq::SliceRandom

source · [−]

pub trait SliceRandom {
-    type Item;
-
-    fn choose<R>(&self, rng: &mut R) -> Option<&Self::Item>
    where
        R: Rng + ?Sized;
-    fn choose_mut<R>(&mut self, rng: &mut R) -> Option<&mut Self::Item>
    where
        R: Rng + ?Sized;
-    fn choose_multiple<R>(
        &self,
        rng: &mut R,
        amount: usize
    ) -> SliceChooseIter<'_, Self, Self::Item>ⓘNotable traits for SliceChooseIter<'a, S, T>impl<'a, S: Index<usize, Output = T> + ?Sized + 'a, T: 'a> Iterator for SliceChooseIter<'a, S, T>    type Item = &'a T;
    where
        R: Rng + ?Sized;
-    fn choose_weighted<R, F, B, X>(
        &self,
        rng: &mut R,
        weight: F
    ) -> Result<&Self::Item, WeightedError>
    where
        R: Rng + ?Sized,
        F: Fn(&Self::Item) -> B,
        B: SampleBorrow<X>,
        X: SampleUniform + for<'a> AddAssign<&'a X> + PartialOrd<X> + Clone + Default;
-    fn choose_weighted_mut<R, F, B, X>(
        &mut self,
        rng: &mut R,
        weight: F
    ) -> Result<&mut Self::Item, WeightedError>
    where
        R: Rng + ?Sized,
        F: Fn(&Self::Item) -> B,
        B: SampleBorrow<X>,
        X: SampleUniform + for<'a> AddAssign<&'a X> + PartialOrd<X> + Clone + Default;
-    fn choose_multiple_weighted<R, F, X>(
        &self,
        rng: &mut R,
        amount: usize,
        weight: F
    ) -> Result<SliceChooseIter<'_, Self, Self::Item>, WeightedError>
    where
        R: Rng + ?Sized,
        F: Fn(&Self::Item) -> X,
        X: Into<f64>;
-    fn shuffle<R>(&mut self, rng: &mut R)
    where
        R: Rng + ?Sized;
-    fn partial_shuffle<R>(
        &mut self,
        rng: &mut R,
        amount: usize
    ) -> (&mut [Self::Item], &mut [Self::Item])
    where
        R: Rng + ?Sized;
-}

Expand description

Extension trait on slices, providing random mutation and sampling methods.

This trait is implemented on all [T] slice types, providing several -methods for choosing and shuffling elements. You must use this trait:

- -

use rand::seq::SliceRandom;
-
-let mut rng = rand::thread_rng();
-let mut bytes = "Hello, random!".to_string().into_bytes();
-bytes.shuffle(&mut rng);
-let str = String::from_utf8(bytes).unwrap();
-println!("{}", str);

Example output (non-deterministic):

l,nmroHado !le
-

Required Associated Types

source

type Item

The element type.

Required Methods

source

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

Returns a reference to one random element of the slice, or None if the -slice is empty.

For slices, complexity is O(1).

Example

use rand::thread_rng;
-use rand::seq::SliceRandom;
-
-let choices = [1, 2, 4, 8, 16, 32];
-let mut rng = thread_rng();
-println!("{:?}", choices.choose(&mut rng));
-assert_eq!(choices[..0].choose(&mut rng), None);

source

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

Returns a mutable reference to one random element of the slice, or -None if the slice is empty.

For slices, complexity is O(1).

source

fn choose_multiple<R>(
 &self,
 rng: &mut R,
 amount: usize
) -> SliceChooseIter<'_, Self, Self::Item>ⓘNotable traits for SliceChooseIter<'a, S, T>`impl<'a, S: Index<usize, Output = T> + ?Sized + 'a, T: 'a> Iterator for SliceChooseIter<'a, S, T> type Item = &'a T;`where
 R: Rng + ?Sized,

Chooses amount elements from the slice at random, without repetition, -and in random order. The returned iterator is appropriate both for -collection into a Vec and filling an existing buffer (see example).

In case this API is not sufficiently flexible, use index::sample.

For slices, complexity is the same as index::sample.

Example

use rand::seq::SliceRandom;
-
-let mut rng = &mut rand::thread_rng();
-let sample = "Hello, audience!".as_bytes();
-
-// collect the results into a vector:
-let v: Vec<u8> = sample.choose_multiple(&mut rng, 3).cloned().collect();
-
-// store in a buffer:
-let mut buf = [0u8; 5];
-for (b, slot) in sample.choose_multiple(&mut rng, buf.len()).zip(buf.iter_mut()) {
-    *slot = *b;
-}

source

fn choose_weighted<R, F, B, X>(
 &self,
 rng: &mut R,
 weight: F
) -> Result<&Self::Item, WeightedError>where
 R: Rng + ?Sized,
 F: Fn(&Self::Item) -> B,
 B: SampleBorrow<X>,
 X: SampleUniform + for<'a> AddAssign<&'a X> + PartialOrd<X> + Clone + Default,

Similar to choose, but where the likelihood of each outcome may be -specified.

The specified function weight maps each item x to a relative -likelihood weight(x). The probability of each item being selected is -therefore weight(x) / s, where s is the sum of all weight(x).

For slices of length n, complexity is O(n). -See also choose_weighted_mut, distributions::weighted.

Example

use rand::prelude::*;
-
-let choices = [('a', 2), ('b', 1), ('c', 1)];
-let mut rng = thread_rng();
-// 50% chance to print 'a', 25% chance to print 'b', 25% chance to print 'c'
-println!("{:?}", choices.choose_weighted(&mut rng, |item| item.1).unwrap().0);

source

fn choose_weighted_mut<R, F, B, X>(
 &mut self,
 rng: &mut R,
 weight: F
) -> Result<&mut Self::Item, WeightedError>where
 R: Rng + ?Sized,
 F: Fn(&Self::Item) -> B,
 B: SampleBorrow<X>,
 X: SampleUniform + for<'a> AddAssign<&'a X> + PartialOrd<X> + Clone + Default,

Similar to choose_mut, but where the likelihood of each outcome may -be specified.

For slices of length n, complexity is O(n). -See also choose_weighted, distributions::weighted.

source

fn choose_multiple_weighted<R, F, X>(
 &self,
 rng: &mut R,
 amount: usize,
 weight: F
) -> Result<SliceChooseIter<'_, Self, Self::Item>, WeightedError>where
 R: Rng + ?Sized,
 F: Fn(&Self::Item) -> X,
 X: Into<f64>,

Similar to choose_multiple, but where the likelihood of each element’s -inclusion in the output may be specified. The elements are returned in an -arbitrary, unspecified order.

If all of the weights are equal, even if they are all zero, each element has -an equal likelihood of being selected.

The complexity of this method depends on the feature partition_at_index. -If the feature is enabled, then for slices of length n, the complexity -is O(n) space and O(n) time. Otherwise, the complexity is O(n) space and -O(n * log amount) time.

Example

use rand::prelude::*;
-
-let choices = [('a', 2), ('b', 1), ('c', 1)];
-let mut rng = thread_rng();
-// First Draw * Second Draw = total odds
-// -----------------------
-// (50% * 50%) + (25% * 67%) = 41.7% chance that the output is `['a', 'b']` in some order.
-// (50% * 50%) + (25% * 67%) = 41.7% chance that the output is `['a', 'c']` in some order.
-// (25% * 33%) + (25% * 33%) = 16.6% chance that the output is `['b', 'c']` in some order.
-println!("{:?}", choices.choose_multiple_weighted(&mut rng, 2, |item| item.1).unwrap().collect::<Vec<_>>());

source

fn shuffle<R>(&mut self, rng: &mut R)where
R: Rng + ?Sized,

Shuffle a mutable slice in place.

For slices of length n, complexity is O(n).

Example

use rand::seq::SliceRandom;
-use rand::thread_rng;
-
-let mut rng = thread_rng();
-let mut y = [1, 2, 3, 4, 5];
-println!("Unshuffled: {:?}", y);
-y.shuffle(&mut rng);
-println!("Shuffled:   {:?}", y);

source

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

Shuffle a slice in place, but exit early.

Returns two mutable slices from the source slice. The first contains -amount elements randomly permuted. The second has the remaining -elements that are not fully shuffled.

This is an efficient method to select amount elements at random from -the slice, provided the slice may be mutated.

If you only need to choose elements randomly and amount > self.len()/2 -then you may improve performance by taking -amount = values.len() - amount and using only the second slice.

If amount is greater than the number of elements in the slice, this -will perform a full shuffle.

For slices, complexity is O(m) where m = amount.

Implementations on Foreign Types

source

impl<T> SliceRandom for [T]

type Item = T

source

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

source

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

source

fn choose_multiple<R>(
 &self,
 rng: &mut R,
 amount: usize
) -> SliceChooseIter<'_, Self, Self::Item>ⓘNotable traits for SliceChooseIter<'a, S, T>`impl<'a, S: Index<usize, Output = T> + ?Sized + 'a, T: 'a> Iterator for SliceChooseIter<'a, S, T> type Item = &'a T;`where
 R: Rng + ?Sized,

source

fn choose_weighted<R, F, B, X>(
 &self,
 rng: &mut R,
 weight: F
) -> Result<&Self::Item, WeightedError>where
 R: Rng + ?Sized,
 F: Fn(&Self::Item) -> B,
 B: SampleBorrow<X>,
 X: SampleUniform + for<'a> AddAssign<&'a X> + PartialOrd<X> + Clone + Default,

source

fn choose_weighted_mut<R, F, B, X>(
 &mut self,
 rng: &mut R,
 weight: F
) -> Result<&mut Self::Item, WeightedError>where
 R: Rng + ?Sized,
 F: Fn(&Self::Item) -> B,
 B: SampleBorrow<X>,
 X: SampleUniform + for<'a> AddAssign<&'a X> + PartialOrd<X> + Clone + Default,

source

fn choose_multiple_weighted<R, F, X>(
 &self,
 rng: &mut R,
 amount: usize,
 weight: F
) -> Result<SliceChooseIter<'_, Self, Self::Item>, WeightedError>where
 R: Rng + ?Sized,
 F: Fn(&Self::Item) -> X,
 X: Into<f64>,

source

fn shuffle<R>(&mut self, rng: &mut R)where
R: Rng + ?Sized,

source

Module rand::seq

Enum rand::seq::index::IndexVec

Implementations

impl IndexVec

pub fn len(&self) -> usize

pub fn is_empty(&self) -> bool

pub fn index(&self, index: usize) -> usize

pub fn into_vec(self) -> Vec<usize>

pub fn iter(&self) -> IndexVecIter<'_>ⓘNotable traits for IndexVecIter<'a>impl<'a> Iterator for IndexVecIter<'a> type Item = usize;

Trait Implementations

impl Clone for IndexVec

fn clone(&self) -> IndexVec

fn clone_from(&mut self, source: &Self)

impl Debug for IndexVec

fn fmt(&self, f: &mut Formatter<'_>) -> Result

impl From<Vec<u32, Global>> for IndexVec

fn from(v: Vec<u32>) -> Self

impl From<Vec<usize, Global>> for IndexVec

fn from(v: Vec<usize>) -> Self

impl IntoIterator for IndexVec

fn into_iter(self) -> IndexVecIntoIterⓘNotable traits for IndexVecIntoIterimpl Iterator for IndexVecIntoIter type Item = usize;

type Item = usize

type IntoIter = IndexVecIntoIter

impl PartialEq<IndexVec> for IndexVec

fn eq(&self, other: &IndexVec) -> bool

fn ne(&self, other: &Rhs) -> bool

Auto Trait Implementations

impl RefUnwindSafe for IndexVec

impl Send for IndexVec

impl Sync for IndexVec

impl Unpin for IndexVec

impl UnwindSafe for IndexVec

Blanket Implementations

impl<T> Any for Twhere T: 'static + ?Sized,

fn type_id(&self) -> TypeId

impl<T> Borrow<T> for Twhere T: ?Sized,

fn borrow(&self) -> &T

impl<T> BorrowMut<T> for Twhere T: ?Sized,

fn borrow_mut(&mut self) -> &mut T

impl<T> From<T> for T

fn from(t: T) -> T

impl<T, U> Into<U> for Twhere U: From<T>,

fn into(self) -> U

impl<T> ToOwned for Twhere T: Clone,

type Owned = T

fn to_owned(&self) -> T

fn clone_into(&self, target: &mut T)

impl<T, U> TryFrom<U> for Twhere U: Into<T>,

type Error = Infallible

fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

impl<T, U> TryInto<U> for Twhere U: TryFrom<T>,

type Error = <U as TryFrom<T>>::Error

fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

impl<V, T> VZip<V> for Twhere V: MultiLane<T>,

fn vzip(self) -> V

Enum rand::seq::index::IndexVecIntoIter

Trait Implementations

impl Clone for IndexVecIntoIter

fn clone(&self) -> IndexVecIntoIterⓘNotable traits for IndexVecIntoIterimpl Iterator for IndexVecIntoIter type Item = usize;

fn clone_from(&mut self, source: &Self)

impl Debug for IndexVecIntoIter

fn fmt(&self, f: &mut Formatter<'_>) -> Result

impl ExactSizeIterator for IndexVecIntoIter

fn len(&self) -> usize

fn is_empty(&self) -> bool

impl Iterator for IndexVecIntoIter

type Item = usize

fn next(&mut self) -> Option<Self::Item>

fn size_hint(&self) -> (usize, Option<usize>)

fn next_chunk<const N: usize>( &mut self) -> Result<[Self::Item; N], IntoIter<Self::Item, N>>where Self: Sized,

fn count(self) -> usizewhere Self: Sized,

fn last(self) -> Option<Self::Item>where Self: Sized,

fn advance_by(&mut self, n: usize) -> Result<(), usize>

fn nth(&mut self, n: usize) -> Option<Self::Item>

fn step_by(self, step: usize) -> StepBy<Self>where Self: Sized,

fn chain<U>(self, other: U) -> Chain<Self, <U as IntoIterator>::IntoIter>where Self: Sized, U: IntoIterator<Item = Self::Item>,

fn zip<U>(self, other: U) -> Zip<Self, <U as IntoIterator>::IntoIter>where Self: Sized, U: IntoIterator,

fn intersperse_with<G>(self, separator: G) -> IntersperseWith<Self, G>where Self: Sized, G: FnMut() -> Self::Item,

fn map<B, F>(self, f: F) -> Map<Self, F>where Self: Sized, F: FnMut(Self::Item) -> B,

fn for_each<F>(self, f: F)where Self: Sized, F: FnMut(Self::Item),

pub fn iter(&self) -> IndexVecIter<'_>ⓘNotable traits for IndexVecIter<'a>`impl<'a> Iterator for IndexVecIter<'a> type Item = usize;`

fn into_iter(self) -> IndexVecIntoIterⓘNotable traits for IndexVecIntoIter`impl Iterator for IndexVecIntoIter type Item = usize;`

impl<T> Any for Twhere
T: 'static + ?Sized,

impl<T> Borrow<T> for Twhere
T: ?Sized,

impl<T> BorrowMut<T> for Twhere
T: ?Sized,

impl<T, U> Into<U> for Twhere
U: From<T>,

impl<T> ToOwned for Twhere
T: Clone,

impl<T, U> TryFrom<U> for Twhere
U: Into<T>,

impl<T, U> TryInto<U> for Twhere
U: TryFrom<T>,

impl<V, T> VZip<V> for Twhere
V: MultiLane<T>,

fn clone(&self) -> IndexVecIntoIterⓘNotable traits for IndexVecIntoIter`impl Iterator for IndexVecIntoIter type Item = usize;`

fn next_chunk<const N: usize>(
&mut self
) -> Result<[Self::Item; N], IntoIter<Self::Item, N>>where
Self: Sized,

fn count(self) -> usizewhere
Self: Sized,

fn last(self) -> Option<Self::Item>where
Self: Sized,

fn step_by(self, step: usize) -> StepBy<Self>where
Self: Sized,

fn chain<U>(self, other: U) -> Chain<Self, <U as IntoIterator>::IntoIter>where
Self: Sized,
U: IntoIterator<Item = Self::Item>,

fn zip<U>(self, other: U) -> Zip<Self, <U as IntoIterator>::IntoIter>where
Self: Sized,
U: IntoIterator,

fn intersperse_with<G>(self, separator: G) -> IntersperseWith<Self, G>where
Self: Sized,
G: FnMut() -> Self::Item,

fn map<B, F>(self, f: F) -> Map<Self, F>where
Self: Sized,
F: FnMut(Self::Item) -> B,

fn for_each<F>(self, f: F)where
Self: Sized,
F: FnMut(Self::Item),

fn filter<P>(self, predicate: P) -> Filter<Self, P>where
Self: Sized,
P: FnMut(&Self::Item) -> bool,

fn filter_map<B, F>(self, f: F) -> FilterMap<Self, F>where
Self: Sized,
F: FnMut(Self::Item) -> Option<B>,

fn enumerate(self) -> Enumerate<Self>where
Self: Sized,

fn peekable(self) -> Peekable<Self>where
Self: Sized,

fn skip_while<P>(self, predicate: P) -> SkipWhile<Self, P>where
Self: Sized,
P: FnMut(&Self::Item) -> bool,

fn take_while<P>(self, predicate: P) -> TakeWhile<Self, P>where
Self: Sized,
P: FnMut(&Self::Item) -> bool,

fn map_while<B, P>(self, predicate: P) -> MapWhile<Self, P>where
Self: Sized,
P: FnMut(Self::Item) -> Option<B>,

fn skip(self, n: usize) -> Skip<Self>where
Self: Sized,

fn take(self, n: usize) -> Take<Self>where
Self: Sized,

fn scan<St, B, F>(self, initial_state: St, f: F) -> Scan<Self, St, F>where
Self: Sized,
F: FnMut(&mut St, Self::Item) -> Option<B>,

fn flat_map<U, F>(self, f: F) -> FlatMap<Self, U, F>where
Self: Sized,
U: IntoIterator,
F: FnMut(Self::Item) -> U,

fn fuse(self) -> Fuse<Self>where
Self: Sized,

fn inspect<F>(self, f: F) -> Inspect<Self, F>where
Self: Sized,
F: FnMut(&Self::Item),

fn by_ref(&mut self) -> &mut Selfwhere
Self: Sized,

fn collect<B>(self) -> Bwhere
B: FromIterator<Self::Item>,
Self: Sized,

fn collect_into<E>(self, collection: &mut E) -> &mut Ewhere
E: Extend<Self::Item>,
Self: Sized,

fn partition<B, F>(self, f: F) -> (B, B)where
Self: Sized,
B: Default + Extend<Self::Item>,
F: FnMut(&Self::Item) -> bool,

fn is_partitioned<P>(self, predicate: P) -> boolwhere
Self: Sized,
P: FnMut(Self::Item) -> bool,

fn try_fold<B, F, R>(&mut self, init: B, f: F) -> Rwhere
Self: Sized,
F: FnMut(B, Self::Item) -> R,
R: Try<Output = B>,

fn try_for_each<F, R>(&mut self, f: F) -> Rwhere
Self: Sized,
F: FnMut(Self::Item) -> R,
R: Try<Output = ()>,

fn fold<B, F>(self, init: B, f: F) -> Bwhere
Self: Sized,
F: FnMut(B, Self::Item) -> B,

fn reduce<F>(self, f: F) -> Option<Self::Item>where
Self: Sized,
F: FnMut(Self::Item, Self::Item) -> Self::Item,

fn try_reduce<F, R>(
&mut self,
f: F
) -> <<R as Try>::Residual as Residual<Option<<R as Try>::Output>>>::TryTypewhere
Self: Sized,
F: FnMut(Self::Item, Self::Item) -> R,
R: Try<Output = Self::Item>,
<R as Try>::Residual: Residual<Option<Self::Item>>,

fn all<F>(&mut self, f: F) -> boolwhere
Self: Sized,
F: FnMut(Self::Item) -> bool,

fn any<F>(&mut self, f: F) -> boolwhere
Self: Sized,
F: FnMut(Self::Item) -> bool,

fn find<P>(&mut self, predicate: P) -> Option<Self::Item>where
Self: Sized,
P: FnMut(&Self::Item) -> bool,

fn find_map<B, F>(&mut self, f: F) -> Option<B>where
Self: Sized,
F: FnMut(Self::Item) -> Option<B>,

fn try_find<F, R>(
&mut self,
f: F
) -> <<R as Try>::Residual as Residual<Option<Self::Item>>>::TryTypewhere
Self: Sized,
F: FnMut(&Self::Item) -> R,
R: Try<Output = bool>,
<R as Try>::Residual: Residual<Option<Self::Item>>,

fn position<P>(&mut self, predicate: P) -> Option<usize>where
Self: Sized,
P: FnMut(Self::Item) -> bool,

fn max_by_key<B, F>(self, f: F) -> Option<Self::Item>where
B: Ord,
Self: Sized,
F: FnMut(&Self::Item) -> B,

fn max_by<F>(self, compare: F) -> Option<Self::Item>where
Self: Sized,
F: FnMut(&Self::Item, &Self::Item) -> Ordering,

fn min_by_key<B, F>(self, f: F) -> Option<Self::Item>where
B: Ord,
Self: Sized,
F: FnMut(&Self::Item) -> B,

fn min_by<F>(self, compare: F) -> Option<Self::Item>where
Self: Sized,
F: FnMut(&Self::Item, &Self::Item) -> Ordering,

fn unzip<A, B, FromA, FromB>(self) -> (FromA, FromB)where
FromA: Default + Extend<A>,
FromB: Default + Extend<B>,
Self: Sized + Iterator<Item = (A, B)>,

fn copied<'a, T>(self) -> Copied<Self>where
T: 'a + Copy,
Self: Sized + Iterator<Item = &'a T>,

fn cloned<'a, T>(self) -> Cloned<Self>where
T: 'a + Clone,
Self: Sized + Iterator<Item = &'a T>,

fn cycle(self) -> Cycle<Self>where
Self: Sized + Clone,

fn array_chunks<const N: usize>(self) -> ArrayChunks<Self, N>where
Self: Sized,

fn sum<S>(self) -> Swhere
Self: Sized,
S: Sum<Self::Item>,

fn product<P>(self) -> Pwhere
Self: Sized,
P: Product<Self::Item>,

fn cmp_by<I, F>(self, other: I, cmp: F) -> Orderingwhere
Self: Sized,
I: IntoIterator,
F: FnMut(Self::Item, <I as IntoIterator>::Item) -> Ordering,

fn partial_cmp<I>(self, other: I) -> Option<Ordering>where
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,
Self: Sized,

fn partial_cmp_by<I, F>(self, other: I, partial_cmp: F) -> Option<Ordering>where
Self: Sized,
I: IntoIterator,
F: FnMut(Self::Item, <I as IntoIterator>::Item) -> Option<Ordering>,

fn eq<I>(self, other: I) -> boolwhere
I: IntoIterator,
Self::Item: PartialEq<<I as IntoIterator>::Item>,
Self: Sized,

fn eq_by<I, F>(self, other: I, eq: F) -> boolwhere
Self: Sized,
I: IntoIterator,
F: FnMut(Self::Item, <I as IntoIterator>::Item) -> bool,

fn ne<I>(self, other: I) -> boolwhere
I: IntoIterator,
Self::Item: PartialEq<<I as IntoIterator>::Item>,
Self: Sized,

fn lt<I>(self, other: I) -> boolwhere
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,
Self: Sized,

fn le<I>(self, other: I) -> boolwhere
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,
Self: Sized,

fn gt<I>(self, other: I) -> boolwhere
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,
Self: Sized,

fn ge<I>(self, other: I) -> boolwhere
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,
Self: Sized,

fn is_sorted_by<F>(self, compare: F) -> boolwhere
Self: Sized,
F: FnMut(&Self::Item, &Self::Item) -> Option<Ordering>,

fn is_sorted_by_key<F, K>(self, f: F) -> boolwhere
Self: Sized,
F: FnMut(Self::Item) -> K,
K: PartialOrd<K>,