std::ranges::views::join_with, std::ranges::join_with_view

Defined in header `<ranges>`
template< ranges::input_range V, ranges::forward_range Pattern > requires ranges::view<V> && ranges::input_range<ranges::range_reference_t<V>> && ranges::view<Pattern> && /concatable/<ranges::range_reference_t<V>, Pattern> class join_with_view : ranges::view_interface<join_with_view<V, Pattern>>	(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 */ constexpr ranges::view auto join_with( R&& r, Pattern&& pattern );		(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
V and ranges::range_reference_t<V> each model forward_range.

join_with_view models bidirectional_range when:

ranges::range_reference_t<V> is a reference,
V, ranges::range_reference_t<V>, and Pattern each models bidirectional_range, and
ranges::range_reference_t<V> and Pattern each model common_range.

join_with_view models common_range when:

ranges::range_reference_t<V> is a reference, and
V and ranges::range_reference_t<V> each model forward_range and common_range.

Nested types

Type	Definition
`InnerRng`	ranges::range_reference_t<V> (exposition-only member type*)

Data members

Member	Description
`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

(constructor)	constructs a `join_with_view` (public member function)
base	returns a copy of the underlying (adapted) view (public member function)
begin	returns an iterator to the beginning (public member function)
end	returns an iterator or a sentinel to the end (public member function)
Inherited from `std::ranges::view_interface`
empty	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>`)
cbegin (C++23)	returns a constant iterator to the beginning of the range (public member function of `std::ranges::view_interface<D>`)
cend (C++23)	returns a sentinel for the constant iterator of the range (public member function of `std::ranges::view_interface<D>`)
operator bool	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>`)
front	returns the first element in the derived view, provided if it satisfies `forward_range` (public member function of `std::ranges::view_interface<D>`)
back	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>`)

Deduction guides

Nested classes

iterator	the iterator type (exposition-only member class template*)
sentinel	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

#include <print>
#include <ranges>
#include <string_view>
#include <list>

int main()
{
    std::list<std::string_view> v{"_", "cpp", "lib", "ranges", "join", "with"};
    std::println("{:s}", v | std::views::join_with('_'));
}

Output:

__cpp_lib_ranges_join_with

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

ranges::join_viewviews::join (C++20)	a `view` consisting of the sequence obtained from flattening a `view` of `range`s (class template) (range adaptor object)
ranges::concat_viewviews::concat (C++26)	a `view` consisting of concatenation of the adapted views (class template) (customization point object)

std::ranges::views::join_with, std::ranges::join_with_view

Nested types

Data members

Member functions

Inherited from `std::ranges::view_interface`

Deduction guides

Nested classes

Notes

Example

Defect reports

See also

std::ranges::views::join_with, std::ranges::join_with_view

Nested types

Data members

Member functions

Inherited from std::ranges::view_interface

Deduction guides

Nested classes

Notes

Example

Defect reports

See also

Inherited from `std::ranges::view_interface`