std::ranges::views::join_with, std::ranges::join_with_view
From cppreference.com
| Defined in header <ranges>
|
||
| template< ranges::input_range V, ranges::forward_range Pattern > requires ranges::view<V> && |
(1) | (since C++23) |
| namespace views { inline constexpr /* unspecified */ join_with = /* unspecified */; |
(2) | (since C++23) |
| Call signature |
||
| template< ranges::viewable_range R, class Pattern > requires /* see below */ |
(since C++23) | |
| template< class Pattern > constexpr /* range adaptor closure */ join_with( Pattern&& pattern ); |
(since C++23) | |
1) A range adaptor that represents
view consisting of the sequence obtained from flattening a view of ranges, with every element of the delimiter inserted in between elements of the view. The delimiter can be a single element or a view of elements. For the definition of /*concatable*/, see std::ranges::concat_view.
2) RangeAdaptorObject. The expression views::join_with(e, f) is expression-equivalent to join_with_view(e, f) for any suitable subexpressions e and f.
join_with_view models input_range.
join_with_view models forward_range when:
- ranges::range_reference_t<V> is a reference, and
-
Vand ranges::range_reference_t<V> each modelforward_range.
join_with_view models bidirectional_range when:
- ranges::range_reference_t<V> is a reference,
-
V, ranges::range_reference_t<V>, andPatterneach modelsbidirectional_range, and - ranges::range_reference_t<V> and
Patterneach modelcommon_range.
join_with_view models common_range when:
- ranges::range_reference_t<V> is a reference, and
-
Vand ranges::range_reference_t<V> each modelforward_rangeandcommon_range.
Nested types
| Type | Definition |
InnerRng
|
ranges::range_reference_t<V> (exposition-only member type*) |
Data members
| Member | Definition |
V base_
|
the underlying (adapted) view (exposition-only member object*) |
Pattern pattern_
|
the pattern object (exposition-only member object*) |
non-propagating-cache <ranges::iterator_t<V>> outer_it_ (present only if V does not model forward_range)
|
the cache of the outer iterator (exposition-only member object*) |
non-propagating-cache <std::remove_cv_t<InnerRng >> inner_ (present only if std::is_reference_v< InnerRng > is false)
|
the cache of the inner range (exposition-only member object*) |
Member functions
constructs a join_with_view (public member function) | |
| returns a copy of the underlying (adapted) 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) | |
Inherited from std::ranges::view_interface | |
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>) |
| 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>) | |
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 if it satisfies bidirectional_range and common_range. (public member function of std::ranges::view_interface<D>) | |
Deduction guides
Nested classes
| the iterator type (exposition-only member class template*) | |
| the sentinel type (exposition-only member class template*) |
Notes
| Feature-test macro | Value | Std | Feature |
|---|---|---|---|
__cpp_lib_ranges_join_with |
202202L |
(C++23) | std::ranges::join_with_view
|
Example
Run this code
#include <iostream> #include <ranges> #include <string_view> #include <vector> int main() { using namespace std::literals; std::vector v{"This"sv, "is"sv, "a"sv, "test."sv}; auto joined = v | std::views::join_with(' '); for (auto c : joined) std::cout << c; std::cout << '\n'; }
Output:
This is a test.
Defect reports
The following behavior-changing defect reports were applied retroactively to previously published C++ standards.
| DR | Applied to | Behavior as published | Correct behavior |
|---|---|---|---|
| LWG 4074 | C++23 | join_with_view was underconstrained
|
updated the constraints |
See also
| (C++20) |
a view consisting of the sequence obtained from flattening a view of ranges(class template) (range adaptor object) |
a view consisting of concatenation of the adapted views(class template) (customization point object) |