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<R> n ); | (since C++23) | |
template< class DifferenceType > constexpr /* range adaptor object */ slide( DifferenceType&& 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) |
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.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.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 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.
Typical implementations of slide_view hold from two to four non-static data members:
view of type V (shown here as base_ for exposition only), n_ for exposition only). 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). 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). |
(C++23) | constructs a slide_view (public member function) |
|
(C++23) | returns an iterator to the beginning (public member function) |
|
(C++23) | returns an iterator or a sentinel to the end (public member function) |
|
(C++23) | returns the number of elements. Provided only if the underlying (adapted) range satisfies sized_range. (public member function) |
Inherited from |
|
|
(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>) |
|
(C++23) | returns a constant iterator to the beginning of the range. (public member function of std::ranges::view_interface<D>) |
|
(C++23) | returns a sentinel for the constant iterator of the range. (public member function of std::ranges::view_interface<D>) |
|
(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>) |
|
(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>) |
|
(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>) |
|
(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>) |
|
(C++23) | the iterator type (exposition-only member class template) |
|
(C++23) | the sentinel type used when slide_view is not a common_range (exposition-only member class template) |
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.
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 |
A link to test: Compiler Explorer.
#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]
|
(C++23) | a view consisting of tuples of references to adjacent elements of the adapted view (class template) (range adaptor object) |
|
(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) |
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