std::ranges::views::stride, std::ranges::stride_view
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Ranges library (C++20)
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Execution control library (C++26)
Ranges library
(exposition-only member object*)
returns the approximate size of the resulting
(public member function) [edit]
returns a constant iterator to the beginning of the range
(public member function of
returns a sentinel for the constant iterator of the range
(public member function of
a
(class template) (range adaptor object)[edit]
a range of
(class template) (range adaptor object)[edit]
(C++23)(C++23)
(C++23)(C++23)
(C++23)(C++23)
(C++26)(C++26)
(C++23)(C++23)
(C++23)(C++23)
(C++23)(C++23)
(C++23)(C++23)
(C++23)(C++23)
(C++23)
(C++23)(C++23)
(C++23)
(C++23)(C++23)
(C++23)(C++23)
(C++23)(C++23)
stride_viewviews::stride
(C++23)(C++23)
(C++23)(C++23)
(C++23)
std::ranges::stride_view
(C++26)
Defined in header
<ranges>
template< ranges::input_range V >
(1)
(since C++23)
requires ranges::view <V>
class stride_view
namespace views {
(2)
(since C++23)
inline constexpr /* unspecified */ stride = /* unspecified */;
Call signature
template< ranges::viewable_range R >
constexpr ranges::view auto stride( R&& r, ranges::range_difference_t <R> n );
(since C++23)
constexpr ranges::view auto stride( R&& r, ranges::range_difference_t <R> n );
template< class DifferenceType >
constexpr /*range adaptor closure*/ stride( DifferenceType&& n );
(since C++23)
constexpr /*range adaptor closure*/ stride( DifferenceType&& n );
Helper templates
1)
stride_view is a range adaptor that takes a view and a number n and produces a view, that consists of elements of the original view by advancing over n elements at a time. This means that each mth element of the produced view is (n * i)th element of the original view, for some non-negative index i.
The elements of the original view, whose "index" is not a multiple of n, are not present in the produced view. Let
S be the size of the original view. Then the size of produced view is:
- (S / n) + (S % n ? 1 : 0), if S >= n; otherwise,
- 1, if S > 0; otherwise,
- 0, and the resulting view is empty.
2) The name views::stride denotes a RangeAdaptorObject. Given subexpressions e and n, the expression views::stride(e, n) is expression-equivalent to stride_view(e, n).
The
n must be greater than 0, otherwise the behavior is undefined.stride_view always models input_range, and models forward_range, bidirectional_range, random_access_range, and/or sized_range, if adapted view type V models the corresponding concept.
stride_view<V> models common_range whenever the underlying view V does.
Contents
[edit] Data members
Member
Description
V base_
the underlying view(exposition-only member object*)
ranges::range_difference_t <V>
(exposition-only member object*)
stride_
the size object (the "stride")(exposition-only member object*)
[edit] Member functions
returns the number of elements, provided only if the underlying (adapted) range satisfies
(public member function) [edit]
sized_range (public member function) [edit]
(C++26)
approximately_sized_range (public member function) [edit]
Inherited from std::ranges::view_interface
returns whether the derived view is empty, provided only if it satisfies
(public member function of
sized_range or forward_range (public member function of
std::ranges::view_interface<D>) [edit]
(C++23)
(public member function of
std::ranges::view_interface<D>) [edit]
(C++23)
(public member function of
std::ranges::view_interface<D>) [edit]
returns whether the derived view is not empty, provided only if ranges::empty is applicable to it
(public member function of
(public member function of
std::ranges::view_interface<D>) [edit]
returns the first element in the derived view, provided if it satisfies
(public member function of
forward_range (public member function of
std::ranges::view_interface<D>) [edit]
returns the last element in the derived view, provided only if it satisfies
(public member function of
bidirectional_range and common_range (public member function of
std::ranges::view_interface<D>) [edit]
returns the
(public member function of
nth element in the derived view, provided only if it satisfies random_access_range (public member function of
std::ranges::view_interface<D>) [edit]
[edit] Deduction guides
[edit] Nested classes
[edit] Helper templates
template< class V >
(since C++23)
constexpr bool ranges::enable_borrowed_range <stride_view<V>> =
This specialization of ranges::enable_borrowed_range makes stride_view satisfy borrowed_range when the underlying view satisfies it.
[edit] Notes
| Feature-test macro | Value | Std | Feature |
|---|---|---|---|
__cpp_lib_ranges_stride |
202207L |
(C++23) | std::ranges::stride_view
|
[edit] Example
Run this code
#include <algorithm> #include <iostream> #include <ranges> #include <string_view> using namespace std::literals; void print(std::ranges::viewable_range auto&& v, std::string_view separator = " ") { for (auto const& x : v) std::cout << x << separator; std::cout << '\n'; } int main() { print(std::views::iota (1, 13) | std::views::stride(3)); print(std::views::iota (1, 13) | std::views::stride(3) | std::views::reverse ); print(std::views::iota (1, 13) | std::views::reverse | std::views::stride(3)); print("0x0!133713337*x//42/A$@"sv | std::views::stride(0B11) | std::views::transform ([](char O) -> char { return 0100 | O; }), ""); }
Output:
1 4 7 10 10 7 4 1 12 9 6 3 password
[edit] References
- C++23 standard (ISO/IEC 14882:2024):
- 26.7.31 Stride view [range.stride]
[edit] See also
(C++23)
view whose Mth element is a view over the Mth through (M + N - 1)th elements of another view (class template) (range adaptor object)[edit]
(C++23)
views that are N-sized non-overlapping successive chunks of the elements of another view (class template) (range adaptor object)[edit]
a
(class template) (range adaptor object)[edit]
view consisting of tuples of references to adjacent elements of the adapted view(class template) (range adaptor object)[edit]