NAME¶

std::ranges::views::zip_transform,std::ranges::zip_transform_view - std::ranges::views::zip_transform,std::ranges::zip_transform_view

Synopsis¶

Defined in header <ranges>
template< std::move_constructible F, ranges::input_range... Views
>

requires (ranges::view<Views> && ...) && (sizeof...(Views) >
0) &&
std::is_object_v<F> && std::regular_invocable<
F&, ranges::range_reference_t<Views>...> && (1) (since C++23)
/*can-reference*/<std::invoke_result_t<
F&, ranges::range_reference_t<Views>...>>
class zip_transform_view

: public ranges::view_interface<zip_transform_view<F,
Views...>>
namespace views {

inline constexpr /*unspecified*/ zip_transform = (2) (since C++23)
/*unspecified*/;

}
Call signature
template< class F, ranges::viewable_range... Rs >

requires /* see below */ (since C++23)

constexpr auto zip_transform( F&& f, Rs&&... rs );

1) zip_transform_view is a range adaptor that takes an invocable object and one or
more views, and produces a view whose i^th element is the result of applying the
invocable object to the i^th elements of all views.
A type T models the exposition-only concept /*can-reference*/ if and only if T& is a
valid type.
2) views::zip_transform is a customization point object.

When calling with one argument f, let FD be std::decay_t<decltype(f)>, if:

* FD models copy_constructible,
* FD& models regular_invocable, and
* std::invoke_result_t<FD&> is an object type,

then views::zip_transform(f) is expression-equivalent to ((void)f,
auto(views::empty<std::decay_t<std::invoke_result_t<FD&>>>)). Otherwise, the call to
views::zip_transform is ill-formed.

When calling with more than one arguments f and rs..., views::zip_transform(f,
rs...) is expression-equivalent to ranges::zip_transform_view(f, rs...).

zip_transform_view models the concepts random_access_range, bidirectional_range,
forward_range, input_range, common_range, and sized_range when the underlying
ranges::zip_view<Views...> models respective concepts.

Member functions¶

constructor constructs a zip_transform_view
(C++23) (public member function)
begin returns an iterator to the beginning
(C++23) (public member function)
end returns an iterator or a sentinel to the end
(C++23) (public member function)
size returns the number of elements. Provided only if each underlying
(C++23) (adapted) range satisfies sized_range.
(public member function)
Inherited from std::ranges::view_interface
empty returns whether the derived view is empty. Provided if it satisfies
(C++20) sized_range or forward_range.
(public member function of std::ranges::view_interface<D>)
cbegin returns a constant iterator to the beginning of the range.
(C++23) (public member function of std::ranges::view_interface<D>)
cend returns a sentinel for the constant iterator of the range.
(C++23) (public member function of std::ranges::view_interface<D>)
operator bool returns whether the derived view is not empty. Provided if
(C++20) 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
(C++20) satisfies forward_range.
(public member function of std::ranges::view_interface<D>)
back returns the last element in the derived view. Provided if it satisfies
(C++20) bidirectional_range and common_range.
(public member function of std::ranges::view_interface<D>)
operator[] returns the n^th element in the derived view. Provided if it satisfies
(C++20) random_access_range.
(public member function of std::ranges::view_interface<D>)

Deduction guides

Member types¶

Member type Definition
InnerView (private) ranges::zip_view<Views...>.
(exposition-only member type*)
* ranges::iterator_t<const InnerView> if Const is true,
ziperator (private) otherwise
* ranges::iterator_t<InnerView>.
(exposition-only member type*)
* ranges::sentinel_t<const InnerView> if Const is true,
zentinel (private) otherwise
* ranges::sentinel_t<InnerView>.
(exposition-only member type*)

Data members

Member object Definition
zip_ (private) An underlying view object of type InnerView
(exposition-only member object*)
fun_ (private) A wrapped invocable object of type movable-box<F>
(exposition-only member object*)

Nested classes

iterator the iterator type
(C++23) (exposition-only member class template*)
sentinel the sentinel type used when the underlying zip_view is not a common_range
(C++23) (exposition-only member class template*)

Notes¶

Feature-test macro Value Std Feature
std::ranges::zip_view,
__cpp_lib_ranges_zip 202110L (C++23) std::ranges::zip_transform_view,
std::ranges::adjacent_view,
std::ranges::adjacent_transform_view

Example¶

// Run this code

#include <array>
#include <iostream>
#include <list>
#include <ranges>
#include <vector>

void print(auto const rem, auto const& r)
{
std::cout << rem << '{';
for (char o[]{0,' ',0}; auto const& e : r)
std::cout << o << e, *o = ',';
std::cout << "}\n";
}

int main()
{
auto v1 = std::vector<float>{1, 2, 3};
auto v2 = std::list<short>{1, 2, 3, 4};
auto v3 = std::to_array({1, 2, 3, 4, 5});

auto add = [](auto a, auto b, auto c) { return a + b + c; };

auto sum = std::views::zip_transform(add, v1, v2, v3);

print("v1: ", v1);
print("v2: ", v2);
print("v3: ", v3);
print("sum: ", sum);
}

Output:¶

v1: {1, 2, 3}
v2: {1, 2, 3, 4}
v3: {1, 2, 3, 4, 5}
sum: {3, 6, 9}

See also¶

ranges::zip_view a view consisting of tuples of references to corresponding
views::zip elements of the adapted views
(C++23) (class template) (customization point object)
ranges::transform_view a view of a sequence that applies a transformation function
views::transform to each element
(C++20) (class template) (range adaptor object)
ranges::elements_view takes a view consisting of tuple-like values and a number N
views::elements and produces a view of N^th element of each tuple
(C++20) (class template) (range adaptor object)