std::ranges::views::slide, std::ranges::slide_view

 

C++

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Feature test macros (C++20)

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Ranges library (C++20)

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Technical specifications

Symbols index

External libraries

 

Ranges library

Range access
begin cbegin end cend	rbegin crbegin rend crend	size ssize data cdata	empty
Range conversions
to (C++23)
Range primitives
range_size_trange_difference_t range_value_t	range_reference_trange_const_reference_trange_rvalue_reference_t   (C++23)	iterator_tconst_iterator_tsentinel_t (C++23)
Dangling iterator handling
dangling	borrowed_iterator_t	borrowed_subrange_t
Range concepts
range borrowed_range    sized_range constant_range (C++23)	common_range view viewable_range	input_range output_range forward_range	bidirectional_range random_access_range contiguous_range
Views
view_interface	subrange
Factories
empty_viewviews::empty iota_viewviews::iota	single_viewviews::single cartesian_product_viewviews::cartesian_product (C++23)(C++23)	basic_istream_viewviews::istream repeat_viewviews::repeat (C++23)(C++23)
Adaptors
ref_view views::all_tviews::all common_viewviews::common owning_view views::counted as_const_viewviews::as_const (C++23)(C++23) as_rvalue_viewviews::as_rvalue (C++23)(C++23)   zip_viewviews::zip (C++23)(C++23) zip_transform_viewviews::zip_transform (C++23)(C++23)	take_viewviews::take take_while_viewviews::take_while drop_viewviews::drop drop_while_viewviews::drop_while adjacent_viewviews::adjacent (C++23)(C++23) views::pairwise (C++23) adjacent_transform_viewviews::adjacent_transform (C++23)(C++23)   views::pairwise_transform (C++23)	elements_viewviews::elements keys_viewviews::keys values_viewviews::values transform_viewviews::transform chunk_viewviews::chunk (C++23)(C++23) chunk_by_viewviews::chunk_by (C++23)(C++23) slide_viewviews::slide (C++23)(C++23)	filter_viewviews::filter split_viewviews::split lazy_split_viewviews::lazy_split reverse_viewviews::reverse join_viewviews::join join_with_viewviews::join_with (C++23)(C++23) stride_viewviews::stride (C++23)(C++23)
Range adaptor objects
Range adaptor closure objects
Helper items
movable-box	simple-view	non-propagating-cache

 

std::ranges::slide_view

Member functions

slide_view::slide_view (C++23)

slide_view::begin (C++23)

slide_view::end (C++23)

slide_view::size (C++23)

Deduction guides

Iterator

Member functions

slide_view::iterator::iterator (C++23)

slide_view::iterator::operator* (C++23)

slide_view::iterator::operator[] (C++23)

slide_view::iterator::operator++ slide_view::iterator::operator++(int) slide_view::iterator::operator-- slide_view::iterator::operator--(int) slide_view::iterator::operator+= slide_view::iterator::operator-= (C++23)(C++23)(C++23)(C++23)(C++23)(C++23)

Non-member functions

operator==(slide_view::iterator) operator<(slide_view::iterator) operator>(slide_view::iterator) operator<=(slide_view::iterator) operator>=(slide_view::iterator) operator<=>(slide_view::iterator) (C++23)(C++23)(C++23)(C++23)(C++23)(C++23)

operator+(slide_view::iterator) operator-(slide_view::iterator) (C++23)(C++23)

Sentinel

Member functions

slide_view::sentinel::sentinel (C++23)

Non-member functions

operator==(slide_view::iterator,slide_view::sentinel) (C++23)

operator-(slide_view::iterator,slide_view::sentinel) (C++23)

 

Defined in header <ranges>
template< ranges::forward_range V >     requires ranges::view<V> class slide_view :     public ranges::view_interface<slide_view<V>>	(1)	(since C++23)
namespace views {     inline constexpr /* unspecified */ slide = /* unspecified */; }	(2)	(since C++23)
Call signature
template< ranges::viewable_range R > constexpr ranges::view auto slide( R&& r, ranges::range_difference_t<V> n );		(since C++23)
template< ranges::forward_range V >     requires ranges::view<V> constexpr __range_adaptor_closure slide( ranges::range_difference_t<V> n );		(since C++23)
Helper concepts
template< class V > concept __slide_caches_nothing =                          // exposition only     ranges::random_access_range<V> && ranges::sized_range<V>;	(3)	(since C++23)
template< class V > concept __slide_caches_last =                             // exposition only     !__slide_caches_nothing<V> &&     ranges::bidirectional_range<V> && ranges::common_range<V>;	(4)	(since C++23)
template< class V > concept __slide_caches_first =                            // exposition only     !__slide_caches_nothing<V> && !__slide_caches_last<V>;	(5)	(since C++23)
Helper templates

1) slide_view is a range adaptor that takes a view and a number n and produces a view whose m^th element (a "window") is a view over the m^th through (m + n - 1)^th elements of the original view.

Let S be the size of the original view. Then the size of produced view is:

• S - n + 1, if S >= n,
• ​0​ otherwise, and the resulting view is empty.

2) The name views::slide denotes a RangeAdaptorObject. Given subexpressions e and n, the expression views::slide(e, n) is expression-equivalent to slide_view(e, n).

If the n is not greater than ​0​ the behavior is undefined.

slide_view always models forward_range, and models bidirectional_range, random_access_range, or sized_range if adapted view type models the corresponding concept.

Expression-equivalent

Expression e is expression-equivalent to expression f, if

• e and f have the same effects, and
• either both are constant subexpressions or else neither is a constant subexpression, and
• either both are potentially-throwing or else neither is potentially-throwing (i.e. noexcept(e) == noexcept(f)).

Data members

Typical implementations of slide_view hold from two to four non-static data members:

• the underlying view of type V (shown here as base_ for exposition only),
• the "window size" of type ranges::range_difference_t<V> (shown here as n_ for exposition only).
• the std::optional-like object (shown here as cached_begin_ for exposition only). May be present only if V models the __slide_caches_first helper concept (4).
• the std::optional-like object (shown here as cached_end_ for exposition only). May be present only if V models the __slide_caches_last helper concept (5).

Member functions

(constructor) (C++23)	constructs a slide_view (public member function)
begin (C++23)	returns an iterator to the beginning (public member function)
end (C++23)	returns an iterator or a sentinel to the end (public member function)
size (C++23)	returns the number of elements. Provided only if the underlying (adapted) range satisfies sized_range. (public member function)
Inherited from std::ranges::view_interface
empty (C++20)	Returns whether the derived view is empty. Provided if it satisfies sized_range or forward_range. (public member function of std::ranges::view_interface<D>)
operator bool (C++20)	Returns whether the derived view is not empty. Provided if ranges::empty is applicable to it. (public member function of std::ranges::view_interface<D>)
front (C++20)	Returns the first element in the derived view. Provided if it satisfies forward_range. (public member function of std::ranges::view_interface<D>)
back (C++20)	Returns the last element in the derived view. Provided if it satisfies bidirectional_range and common_range. (public member function of std::ranges::view_interface<D>)
operator[] (C++20)	Returns the nth element in the derived view. Provided if it satisfies random_access_range. (public member function of std::ranges::view_interface<D>)

Nested classes

iterator (C++23)	the iterator type (exposition-only member class template)
sentinel (C++23)	the sentinel type used when slide_view is not a common_range (exposition-only member class template)

Helper templates

template< class V >     inline constexpr bool ranges::enable_borrowed_range<slide_view<V>> =         ranges::enable_borrowed_range<V>;		(since C++23)

This specialization of ranges::enable_borrowed_range makes slide_view satisfy borrowed_range when the underlying view satisfies it.

Notes

There is a similarity between ranges::adjacent_view and ranges::slide_view — they both produce a "sliding window" of the size N, and, given a view of the size S, where S >= N > 0, they both will have the same size: S - N + 1. The difference between these view adaptors are:

View adaptor	value_type	The window size N
ranges::adjacent_view	a tuple-like object	a template parameter
ranges::slide_view	a range	a runtime parameter

Feature-test macro	Value	Std	Comment
__cpp_lib_ranges_slide	202202L	(C++23)	std::ranges::slide_view

Example

A link to test: Compiler Explorer.

Run this code

#include <algorithm>
#include <iostream>
#include <ranges>
 
auto print_subrange = [](std::ranges::viewable_range auto&& r)
{
    std::cout << "[";
    for (int pos{}; auto elem : r)
        std::cout << (pos++ ? " " : "") << elem;
    std::cout << "] ";
};
 
int main()
{
    const auto v = {1, 2, 3, 4, 5, 6};
 
    for (const unsigned width : std::views::iota(1U, 1U + v.size()))
    {
        auto const windows = v | std::views::slide(width);
        std::cout << "All sliding windows of width " << width << ": ";
        std::ranges::for_each(windows, print_subrange);
        std::cout << '\n';
    }
}

Output:

All sliding windows of width 1: [1] [2] [3] [4] [5] [6]
All sliding windows of width 2: [1 2] [2 3] [3 4] [4 5] [5 6]
All sliding windows of width 3: [1 2 3] [2 3 4] [3 4 5] [4 5 6]
All sliding windows of width 4: [1 2 3 4] [2 3 4 5] [3 4 5 6]
All sliding windows of width 5: [1 2 3 4 5] [2 3 4 5 6]
All sliding windows of width 6: [1 2 3 4 5 6]

References

• C++23 standard (ISO/IEC 14882:2023):

• 26.7.28 Slide view [range.slide]

See also

ranges::adjacent_viewviews::adjacent (C++23)	a view consisting of tuples of references to adjacent elements of the adapted view (class template) (range adaptor object)
ranges::chunk_viewviews::chunk (C++23)	a range of views that are N-sized non-overlapping successive chunks of the elements of another view (class template) (range adaptor object)