std::ranges:: views:: slide, std::ranges:: slide_view
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Defined in header
<ranges>
|
||
|
template
<
ranges::
forward_range
V
>
requires
ranges::
view
<
V
>
|
(1) | (since C++23) |
|
namespace
views
{
inline
constexpr
/* unspecified */
slide
=
/* unspecified */
;
|
(2) | (since C++23) |
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Call signature
|
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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) | |
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Helper concepts
|
||
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template
<
class
V
>
concept
/*slide-caches-nothing*/
=
|
(3) | ( exposition only* ) |
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template
<
class
V
>
concept
/*slide-caches-last*/
=
|
(4) | ( exposition only* ) |
|
template
<
class
V
>
concept
/*slide-caches-first*/
=
|
(5) | ( exposition only* ) |
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
[
m
,
m + n - 1
]
elements of the original view.
- s - n + 1 , if s >= n ,
- 0 otherwise, and the resulting view is empty.
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.
Contents |
Data members
| Member | Description |
V
base_
|
the underlying view
( exposition-only member object* ) |
ranges::
range_difference_t
<
V
>
n_
|
the “window” size
( exposition-only member object* ) |
non-propagating-cache
<
ranges::
iterator_t
<
V
>>
cached_begin_
(present only if
V
models the
slide-caches-first
)
|
an object that caches the result of
begin()
( exposition-only member object* ) |
non-propagating-cache
<
ranges::
iterator_t
<
V
>>
cached_end_
(present only if
V
models the
slide-caches-last
)
|
an object that caches the result of
end()
( exposition-only member object* ) |
Member functions
constructs a
slide_view
(public member function) |
|
|
returns an iterator to the beginning
(public member function) |
|
|
returns an iterator or a sentinel to the end
(public member function) |
|
returns the number of elements, provided only if the underlying (adapted) range satisfies
sized_range
(public member function) |
|
|
(C++26)
|
returns the approximate size of the resulting
approximately_sized_range
(public member function) |
Inherited from std::ranges::view_interface |
|
returns whether the derived view is empty, provided only 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>
)
|
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returns whether the derived view is not empty, provided only if
ranges::empty
is applicable to it
(public member function of
std::ranges::view_interface<D>
)
|
|
returns the first element in the derived view, provided if it satisfies
forward_range
(public member function of
std::ranges::view_interface<D>
)
|
|
returns the last element in the derived view, provided only if it satisfies
bidirectional_range
and
common_range
(public member function of
std::ranges::view_interface<D>
)
|
|
returns the
n
th
element in the derived view, provided only if it satisfies
random_access_range
(public member function of
std::ranges::view_interface<D>
)
|
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Deduction guides
Nested classes
|
(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* ) |
Helper templates
|
template
<
class
V
>
constexpr
bool
ranges::
enable_borrowed_range
<
slide_view
<
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 are similarities between ranges::adjacent_view and ranges::slide_view :
-
Both create “sliding window” of size
N. -
Both have the same size
S - N + 1, whereSis the size of an adaptedviewsuch thatS >= N > 0.
The following table shows the differences between these adaptors:
| View adaptor |
value_type
|
The window size
N
|
|---|---|---|
| ranges:: adjacent_view | std::tuple | A template parameter |
| ranges :: slide_view | ranges:: range | A runtime argument |
| Feature-test macro | Value | Std | Feature |
|---|---|---|---|
__cpp_lib_ranges_slide
|
202202L
|
(C++23) |
std::ranges::slide_view
|
Example
#include <algorithm> #include <initializer_list> #include <iostream> #include <ranges> auto print_subrange = [](std::ranges::viewable_range auto&& r) { std::cout << '['; for (char space[]{0,0}; auto elem : r) std::cout << space << elem, *space = ' '; std::cout << "] "; }; int main() { const auto v = {1, 2, 3, 4, 5, 6}; std::cout << "All sliding windows of width:\n"; for (const unsigned width : std::views::iota(1U, 1U + v.size())) { auto const windows = v | std::views::slide(width); std::cout << "W = " << width << ": "; std::ranges::for_each(windows, print_subrange); std::cout << '\n'; } }
Output:
All sliding windows of width W: W = 1: [1] [2] [3] [4] [5] [6] W = 2: [1 2] [2 3] [3 4] [4 5] [5 6] W = 3: [1 2 3] [2 3 4] [3 4 5] [4 5 6] W = 4: [1 2 3 4] [2 3 4 5] [3 4 5 6] W = 5: [1 2 3 4 5] [2 3 4 5 6] W = 6: [1 2 3 4 5 6]
References
- C++23 standard (ISO/IEC 14882:2024):
-
- 26.7.29 Slide view [range.slide]
See also
a
view
consisting of tuples of references to adjacent elements of the adapted view
(class template) (range adaptor object) |
|
|
(C++23)
|
a range of
view
s
that are
N
-sized non-overlapping successive chunks of the elements of another
view
(class template) (range adaptor object) |