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

 

C++

Compiler support

Freestanding and hosted

Language

Standard library headers

Named requirements

Feature test macros (C++20)

Language support library

Concepts library (C++20)

Metaprogramming library (C++11)

Diagnostics library

General utilities library

Strings library

Containers library

Iterators library

Ranges library (C++20)

Algorithms library

Numerics library

Localizations library

Input/output library

Filesystem library (C++17)

Regular expressions library (C++11)

Concurrency support library (C++11)

Technical specifications

Symbols index

External libraries

 

Ranges library

Range access
begin cbegin end cend	rbegin crbegin rend crend	size ssize data cdata	empty
Range conversions
to (C++23)
Range primitives
range_size_trange_difference_t range_value_t	range_reference_trange_const_reference_trange_rvalue_reference_t   (C++23)	iterator_tconst_iterator_tsentinel_t (C++23)
Dangling iterator handling
dangling	borrowed_iterator_t	borrowed_subrange_t
Range concepts
range borrowed_range    sized_range constant_range (C++23)	common_range view viewable_range	input_range output_range forward_range	bidirectional_range random_access_range contiguous_range
Views
view_interface	subrange
Factories
empty_viewviews::empty iota_viewviews::iota	single_viewviews::single basic_istream_viewviews::istream	repeat_viewviews::repeat (C++23)(C++23)
Adaptors
ref_view views::all_tviews::all common_viewviews::common owning_view views::counted reverse_viewviews::reverse zip_viewviews::zip (C++23)(C++23) as_const_viewviews::as_const (C++23)(C++23) as_rvalue_viewviews::as_rvalue (C++23)(C++23)	take_viewviews::take take_while_viewviews::take_while drop_viewviews::drop drop_while_viewviews::drop_while zip_transform_viewviews::zip_transform (C++23)(C++23) adjacent_transform_viewviews::adjacent_transform (C++23)(C++23)   cartesian_product_viewviews::cartesian_product (C++23)(C++23)	elements_viewviews::elements keys_viewviews::keys values_viewviews::values transform_viewviews::transform adjacent_viewviews::adjacent (C++23)(C++23) slide_viewviews::slide (C++23)(C++23) stride_viewviews::stride (C++23)(C++23)	filter_viewviews::filter join_viewviews::join split_viewviews::split lazy_split_viewviews::lazy_split join_with_viewviews::join_with (C++23)(C++23) chunk_viewviews::chunk (C++23)(C++23) chunk_by_viewviews::chunk_by (C++23)(C++23)
Range adaptor objects
Range adaptor closure objects
Helper items
copyable-box	simple-view

 

std::ranges::zip_transform_view

Member functions

zip_transform_view::zip_transform_view (C++23)

zip_transform_view::begin (C++23)

zip_transform_view::end (C++23)

zip_transform_view::size (C++23)

Deduction guides

Iterator

zip_transform_view::iterator::iterator (C++23)

zip_transform_view::iterator::operator* (C++23)

zip_transform_view::iterator::operator[] (C++23)

zip_transform_view::iterator::operator++ zip_transform_view::iterator::operator++(int) zip_transform_view::iterator::operator-- zip_transform_view::iterator::operator--(int) zip_transform_view::iterator::operator+= zip_transform_view::iterator::operator-= (C++23)(C++23)(C++23)(C++23)(C++23)(C++23)

operator==(zip_transform_view::iterator) operator<(zip_transform_view::iterator) operator>(zip_transform_view::iterator) operator<=(zip_transform_view::iterator) operator>=(zip_transform_view::iterator) operator<=>(zip_transform_view::iterator) (C++23)(C++23)(C++23)(C++23)(C++23)(C++23)

operator+(zip_transform_view::iterator) operator-(zip_transform_view::iterator) (C++23)(C++23)

Sentinel

zip_transform_view::sentinel::sentinel (C++23)

operator==(zip_transform_view::sentinel) (C++23)

operator-(zip_transform_view::sentinel) (C++23)

 

Defined in header <ranges>
template< std::copy_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>...> &&               /*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...>>	(1)	(since C++23)
namespace views {     inline constexpr /*unspecified*/ zip_transform = /*unspecified*/; }	(2)	(since C++23)
Call signature
template< class F, ranges::viewable_range... Rs >     requires /* see below */ constexpr auto zip_transform( F&& f, Rs&&... rs );		(since C++23)

1) zip_transform_view is a range adaptor that takes an invocable object and one or more views, and produces a view whose ith element is the result of applying the invocable object to the ith 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.

Customization point objects

The name views::zip_transform denotes a customization point object, which is a const function object of a literal semiregular class type. For exposition purposes, the cv-unqualified version of its type is denoted as __zip_transform_fn.

All instances of __zip_transform_fn are equal. The effects of invoking different instances of type __zip_transform_fn on the same arguments are equivalent, regardless of whether the expression denoting the instance is an lvalue or rvalue, and is const-qualified or not (however, a volatile-qualified instance is not required to be invocable). Thus, views::zip_transform can be copied freely and its copies can be used interchangeably.

Given a set of types Args..., if std::declval<Args>()... meet the requirements for arguments to views::zip_transform above, __zip_transform_fn models

• std::invocable<__zip_transform_fn, Args...>,
• std::invocable<const __zip_transform_fn, Args...>,
• std::invocable<__zip_transform_fn&, Args...>, and
• std::invocable<const __zip_transform_fn&, Args...>.
  

Otherwise, no function call operator of __zip_transform_fn participates in overload resolution.

Expression-equivalent

Expression e is expression-equivalent to expression f, if

• e and f have the same effects, and
• either both are constant subexpressions or else neither is a constant subexpression, and
• either both are potentially-throwing or else neither is potentially-throwing (i.e. noexcept(e) == noexcept(f)).

Data members

Typical implementations of zip_transform_view hold two non-static data members:

• an underlying view object of type InnerView (shown here as zip_ for exposition only), and
• a wrapped invocable object of type copyable-box<F> (shown here as fun_ for exposition only).

Member functions

(constructor) (C++23)	constructs a zip_transform_view (public member function)
begin (C++23)	returns an iterator to the beginning (public member function)
end (C++23)	returns an iterator or a sentinel to the end (public member function)
size (C++23)	returns the number of elements. Provided only if each underlying (adapted) range satisfies sized_range. (public member function)
Inherited from std::ranges::view_interface
empty (C++20)	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>)
operator bool (C++20)	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>)
front (C++20)	Returns the first element in the derived view. Provided if it satisfies forward_range. (public member function of std::ranges::view_interface<D>)
back (C++20)	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>)
operator[] (C++20)	Returns the nth element in the derived view. Provided if it satisfies random_access_range. (public member function of std::ranges::view_interface<D>)

Member types

Member type	Definition
InnerView (private)	ranges::zip_view<Views...>. The name is for exposition only. (typedef)
ziperator (private)	ranges::iterator_t<const InnerView> if Const is true, otherwise ranges::iterator_t<InnerView>. The name is for exposition only. (alias template)
zentinel (private)	ranges::sentinel_t<const InnerView> if Const is true, otherwise ranges::sentinel_t<InnerView>. The name is for exposition only. (alias template)

Nested classes

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

Notes

Feature-test macro:

__cpp_lib_ranges_zip

Example

Run this code

#include <list>
#include <array>
#include <ranges>
#include <vector>
#include <iostream>
 
void print(auto const rem, auto const& r) {
    for (std::cout << rem; auto const& e : r)
        std::cout << e << ' ';
    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_viewviews::zip (C++23)	a view consisting of tuples of references to corresponding elements of the adapted views (class template) (customization point object)
ranges::transform_viewviews::transform (C++20)	a view of a sequence that applies a transformation function to each element (class template) (range adaptor object)