Struct MergedIter 

pub struct MergedIter<const STABLE_TIE_BREAKING: bool, S, Cmp> { /* private fields */ }

An iterator that pulls the smallest item from multiple iterators.

MergedIter is created by [Merged]. It merges items from several base iterators based on a comparison function.

Examples

use iter_merge::Merged;

let iter1 = vec![1, 3, 5];
let iter2 = vec![2, 4, 6];

let mut merged = Merged::new([iter1, iter2]).build();
let result = merged.into_vec();

assert_eq!(result, vec![1, 2, 3, 4, 5, 6]);

Implementations

impl<const STABLE_TIE_BREAKING: bool, S, Cmp, Item, Iter> MergedIter<STABLE_TIE_BREAKING, S, Cmp>

where Iter: Iterator<Item = Item>, Cmp: Fn(&Item, &Item) -> Ordering, S: Storage<Item = (Item, Iter)>,

pub fn add_iter(&mut self, iter: impl IntoIterator<IntoIter = Iter>)

Adds a single iterator to the merge.

This method allows you to dynamically add iterators to an existing MergedIter. The new iterator will be integrated into the merge according to the comparison function, maintaining the sorted order of the output.

Empty iterators are ignored and do not affect the merge state.

Arguments

• iter - An iterator (or anything that implements IntoIterator) to add to the merge

Examples

use iter_merge::Merged;

let mut merged = Merged::new([vec![2, 5, 8]]).build();

assert_eq!(merged.next(), Some(2));

// Add another iterator dynamically
merged.add_iter(vec![1, 4, 7]);
assert_eq!(merged.next(), Some(1));

merged.add_iter(vec![3, 6, 9]);

let result = merged.into_vec();
assert_eq!(result, vec![3, 4, 5, 6, 7, 8, 9]);

pub fn add_iters( &mut self, iters: impl IntoIterator<Item = impl IntoIterator<IntoIter = Iter>>, )

Adds multiple iterators to the merge at once.

This method efficiently adds multiple iterators to an existing MergedIter in a single operation. It’s more efficient than calling add_iter multiple times because it can optimize memory allocation and minimize index recalculations.

Empty iterators in the collection are automatically filtered out and ignored.

Arguments

• iters - A collection of iterators to add to the merge. Each element should implement IntoIterator with the same item type as the existing merge.

Performance

This method attempts to reserve storage space based on the size hint of the input collection, which can improve performance by reducing memory reallocations.

Examples

use iter_merge::Merged;

let mut merged = Merged::new([vec![1, 6, 11]]).build();

// Add multiple iterators at once
merged.add_iters([
    vec![2, 7, 12],
    vec![3, 8, 13],
    vec![4, 9, 14],
    vec![5, 10, 15],
]);

let result = merged.into_vec();
assert_eq!(
    result,
    vec![1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15]
);

pub fn replace_cmp<F>(self, cmp: F) -> MergedIter<STABLE_TIE_BREAKING, S, F>

where F: Fn(&Item, &Item) -> Ordering,

Replaces the comparison function and returns a new MergedIter.

This method consumes the current iterator and creates a new one with a different comparison function. The new iterator will use the provided comparison function to determine the ordering of items from the merged iterators.

Arguments

• cmp - A function that compares two items and returns an Ordering

Examples

use std::cmp::Ordering;

use iter_merge::Merged;

let mut merged = Merged::new([vec![1, 4], vec![2, 5], vec![3, 6]]).build();

assert_eq!(merged.next(), Some(1));
assert_eq!(merged.next(), Some(2));
assert_eq!(merged.next(), Some(3));
// Reverse the ordering
let mut merged = merged.replace_cmp(|a, b| b.cmp(a));
assert_eq!(merged.next(), Some(6));
assert_eq!(merged.next(), Some(5));
assert_eq!(merged.next(), Some(4));

pub fn into_vec(&mut self) -> Vec<Item>

Consumes the iterator and produces a Vec of its items.

This method is an optimization over collect::<Vec<_>>(). It can be more efficient, specifically when only one iterator remains, as it can extend the result vector with the remaining items of that iterator directly.

Examples

use iter_merge::Merged;

let iter1 = vec![1, 3, 5];
let iter2 = vec![2, 4, 6];

let mut merged = Merged::new([iter1, iter2]).build();
let result = merged.into_vec();

assert_eq!(result, vec![1, 2, 3, 4, 5, 6]);

pub fn peek<'a>(&'a mut self) -> Option<&'a Item>

where Iter: 'a,

Returns a reference to the next item that will be returned by next() without consuming it.

This method behaves identically to Peekable::peek from the standard library: it returns a reference to the next item, or None if the iterator is empty.

Examples

use iter_merge::Merged;

let iter1 = vec![1, 3, 5];
let iter2 = vec![2, 4, 6];

let mut merged = Merged::new([iter1, iter2]).build();

assert_eq!(merged.peek(), Some(&1));
assert_eq!(merged.next(), Some(1));
assert_eq!(merged.peek(), Some(&2));

pub fn next_if(&mut self, func: impl FnOnce(&Item) -> bool) -> Option<Item>

Returns the next item of the iterator if it satisfies a predicate.

This method behaves identically to Peekable::next_if from the standard library: it returns the next item if it satisfies the predicate, otherwise returns None.

Examples

use iter_merge::Merged;

let iter1 = vec![1, 1, 2, 3];
let iter2 = vec![1, 4];

let mut merged = Merged::new([iter1, iter2]).build();

// Consume all 1s
while let Some(item) = merged.next_if(|&x| x == 1) {
    assert_eq!(item, 1);
}

assert_eq!(merged.next(), Some(2));

pub fn next_if_eq<T>(&mut self, expected: &T) -> Option<Item>

where T: ?Sized, Item: PartialEq<T>,

Returns the next item of the iterator if it is equal to a given value.

This method behaves identically to Peekable::next_if_eq from the standard library: it returns the next item if it is equal to the given value, otherwise returns None.

This is a convenience method that is equivalent to next_if(|item| item == expected).

Examples

use iter_merge::Merged;

let iter1 = vec![1, 1, 2, 3];
let iter2 = vec![1, 4];

let mut merged = Merged::new([iter1, iter2]).build();

// Consume all 1s
while let Some(item) = merged.next_if_eq(&1) {
    assert_eq!(item, 1);
}

assert_eq!(merged.next(), Some(2));

pub fn break_up(self) -> S

Consumes the MergedIter iterator and returns the remaining iterators.

This method returns the internal storage, which contains the remaining “peeked” items and their associated iterators. Each element in the returned storage is a tuple of the form (Item, Iter), where:

• Item is the “peeked” value from that component iterator,
• Iter is the remaining iterator for that component.

The order of the elements in the storage may be different from the order of original iterators if [Merged::arbitrary_tie_breaking] was used.

If an input iterator was fully consumed, it will be missing from the returned storage.

Examples

use iter_merge::Merged;

let iter1 = vec![1, 3];
let iter2 = vec![2, 4];
let mut merged = Merged::new([iter1, iter2]).build();

assert_eq!(merged.next(), Some(1));

let mut storage = merged.break_up();

assert_eq!(storage[0].0, 3);
assert_eq!(storage[0].1.next(), None);
assert_eq!(storage[1].0, 2);
assert_eq!(storage[1].1.next(), Some(4));
assert_eq!(storage[1].1.next(), None);

Trait Implementations

impl<const STABLE_TIE_BREAKING: bool, S, Cmp, Item, Iter> Clone for MergedIter<STABLE_TIE_BREAKING, S, Cmp>

where Iter: Iterator<Item = Item>, Cmp: Clone + Fn(&Item, &Item) -> Ordering, S: Clone + Storage<Item = (Item, Iter)>,

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<const STABLE_TIE_BREAKING: bool, S: Debug, Cmp: Debug> Debug for MergedIter<STABLE_TIE_BREAKING, S, Cmp>

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

Formats the value using the given formatter.

impl<const STABLE_TIE_BREAKING: bool, Item, Iter, S, Cmp> Iterator for MergedIter<STABLE_TIE_BREAKING, S, Cmp>

where Iter: Iterator<Item = Item>, S: Storage<Item = (Item, Iter)>, Cmp: Fn(&Item, &Item) -> Ordering,

type Item = Item

The type of the elements being iterated over.

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

Advances the iterator and returns the next value.

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

Returns the bounds on the remaining length of the iterator.

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.

fn count(self) -> usize

where Self: Sized,

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

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

where Self: Sized,

Consumes the iterator, returning the last element.

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

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

Advances the iterator by n elements.

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

Returns the nth element of the iterator.

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.

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

where Self: Sized, U: IntoIterator<Item = Self::Item>,

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

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

where Self: Sized, U: IntoIterator,

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

fn intersperse(self, separator: Self::Item) -> Intersperse<Self>

where Self: Sized, Self::Item: Clone,

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

Creates a new iterator which places a copy of separator between adjacent items of the original iterator.

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.

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.

fn for_each<F>(self, f: F)

where Self: Sized, F: FnMut(Self::Item),

Calls a closure on each element of an iterator.

fn filter<P>(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.

fn filter_map<B, F>(self, f: F) -> FilterMap<Self, F>

where Self: Sized, F: FnMut(Self::Item) -> Option<B>,

Creates an iterator that both filters and maps.

fn enumerate(self) -> Enumerate<Self>

where Self: Sized,

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

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.

fn skip_while<P>(self, predicate: P) -> SkipWhile<Self, P>

where Self: Sized, P: FnMut(&Self::Item) -> bool,

Creates an iterator that skips elements based on a predicate.

fn take_while<P>(self, predicate: P) -> TakeWhile<Self, P>

where Self: Sized, P: FnMut(&Self::Item) -> bool,

Creates an iterator that yields elements based on a predicate.

fn map_while<B, P>(self, predicate: P) -> MapWhile<Self, P>

where Self: Sized, P: FnMut(Self::Item) -> Option<B>,

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

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

where Self: Sized,

Creates an iterator that skips the first n elements.

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.

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>,

An iterator adapter which, like fold, holds internal state, but unlike fold, produces a new iterator.

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.

fn flatten(self) -> Flatten<Self>

where Self: Sized, Self::Item: IntoIterator,

Creates an iterator that flattens nested structure.

fn map_windows<F, R, const N: usize>(self, f: F) -> MapWindows<Self, F, N>

where Self: Sized, F: FnMut(&[Self::Item; N]) -> R,

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

Calls the given function f for each contiguous window of size N over self and returns an iterator over the outputs of f. Like slice::windows(), the windows during mapping overlap as well.

fn fuse(self) -> Fuse<Self>

where Self: Sized,

Creates an iterator which ends after the first None.

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.

fn by_ref(&mut self) -> &mut Self

where Self: Sized,

Creates a “by reference” adapter for this instance of Iterator.

fn collect<B>(self) -> B

where B: FromIterator<Self::Item>, Self: Sized,

Transforms an iterator into a collection.

fn try_collect<B>( &mut self, ) -> <<Self::Item as Try>::Residual as Residual<B>>::TryType

where Self: Sized, Self::Item: Try, <Self::Item as Try>::Residual: Residual<B>, B: FromIterator<<Self::Item as Try>::Output>,

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

Fallibly transforms an iterator into a collection, short circuiting if a failure is encountered.

fn collect_into<E>(self, collection: &mut E) -> &mut E

where 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.

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.

fn is_partitioned<P>(self, predicate: P) -> bool

where 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.

fn try_fold<B, F, R>(&mut self, init: B, f: F) -> R

where 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.

fn try_for_each<F, R>(&mut self, f: F) -> R

where 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.

fn fold<B, F>(self, init: B, f: F) -> B

where Self: Sized, F: FnMut(B, Self::Item) -> B,

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

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.

fn try_reduce<R>( &mut self, f: impl FnMut(Self::Item, Self::Item) -> R, ) -> <<R as Try>::Residual as Residual<Option<<R as Try>::Output>>>::TryType

where Self: Sized, 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.

fn all<F>(&mut self, f: F) -> bool

where Self: Sized, F: FnMut(Self::Item) -> bool,

Tests if every element of the iterator matches a predicate.

fn any<F>(&mut self, f: F) -> bool

where Self: Sized, F: FnMut(Self::Item) -> bool,

Tests if any element of the iterator matches a predicate.

fn find<P>(&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.

fn find_map<B, F>(&mut self, f: F) -> Option<B>

where Self: Sized, F: FnMut(Self::Item) -> Option<B>,

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

fn try_find<R>( &mut self, f: impl FnMut(&Self::Item) -> R, ) -> <<R as Try>::Residual as Residual<Option<Self::Item>>>::TryType

where Self: Sized, 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.

fn position<P>(&mut self, predicate: P) -> Option<usize>

where Self: Sized, P: FnMut(Self::Item) -> bool,

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

fn max(self) -> Option<Self::Item>

where Self: Sized, Self::Item: Ord,

Returns the maximum element of an iterator.

fn min(self) -> Option<Self::Item>

where Self: Sized, Self::Item: Ord,

Returns the minimum element of an iterator.

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.

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.

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.

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.

fn unzip<A, B, FromA, FromB>(self) -> (FromA, FromB)

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

Converts an iterator of pairs into a pair of containers.

fn copied<'a, T>(self) -> Copied<Self>

where T: Copy + 'a, Self: Sized + Iterator<Item = &'a T>,

Creates an iterator which copies all of its elements.

fn cloned<'a, T>(self) -> Cloned<Self>

where T: Clone + 'a, Self: Sized + Iterator<Item = &'a T>,

Creates an iterator which clones all of its elements.

fn cycle(self) -> Cycle<Self>

where Self: Sized + Clone,

Repeats an iterator endlessly.

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.

fn sum<S>(self) -> S

where Self: Sized, S: Sum<Self::Item>,

Sums the elements of an iterator.

fn product<P>(self) -> P

where Self: Sized, P: Product<Self::Item>,

Iterates over the entire iterator, multiplying all the elements

fn cmp<I>(self, other: I) -> Ordering

where I: IntoIterator<Item = Self::Item>, Self::Item: Ord, Self: Sized,

Lexicographically compares the elements of this Iterator with those of another.

fn cmp_by<I, F>(self, other: I, cmp: F) -> Ordering

where Self: Sized, I: IntoIterator, F: FnMut(Self::Item, <I as IntoIterator>::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.

fn partial_cmp<I>(self, other: I) -> Option<Ordering>

where I: IntoIterator, Self::Item: PartialOrd<<I as IntoIterator>::Item>, Self: Sized,

Lexicographically compares the PartialOrd elements of this Iterator with those of another. The comparison works like short-circuit evaluation, returning a result without comparing the remaining elements. As soon as an order can be determined, the evaluation stops and a result is returned.

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>,

🔬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.

fn eq<I>(self, other: I) -> bool

where I: IntoIterator, Self::Item: PartialEq<<I as IntoIterator>::Item>, Self: Sized,

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

fn eq_by<I, F>(self, other: I, eq: F) -> bool

where Self: Sized, I: IntoIterator, F: FnMut(Self::Item, <I as IntoIterator>::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.

fn ne<I>(self, other: I) -> bool

where I: IntoIterator, Self::Item: PartialEq<<I as IntoIterator>::Item>, Self: Sized,

Determines if the elements of this Iterator are not equal to those of another.

fn lt<I>(self, other: I) -> bool

where I: IntoIterator, Self::Item: PartialOrd<<I as IntoIterator>::Item>, Self: Sized,

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

fn le<I>(self, other: I) -> bool

where I: IntoIterator, Self::Item: PartialOrd<<I as IntoIterator>::Item>, Self: Sized,

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

fn gt<I>(self, other: I) -> bool

where I: IntoIterator, Self::Item: PartialOrd<<I as IntoIterator>::Item>, Self: Sized,

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

fn ge<I>(self, other: I) -> bool

where I: IntoIterator, Self::Item: PartialOrd<<I as IntoIterator>::Item>, Self: Sized,

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

fn is_sorted(self) -> bool

where Self: Sized, Self::Item: PartialOrd,

Checks if the elements of this iterator are sorted.

fn is_sorted_by<F>(self, compare: F) -> bool

where Self: Sized, F: FnMut(&Self::Item, &Self::Item) -> bool,

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

fn is_sorted_by_key<F, K>(self, f: F) -> bool

where Self: Sized, F: FnMut(Self::Item) -> K, K: PartialOrd,

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