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std::ranges::views::zip, std::ranges::zip_view

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< cpp‎ | ranges
 
 
Ranges library
 
std::ranges::zip_view
Member functions
Non-member functions
 
Defined in header <ranges>
template< ranges::input_range... Views >

    requires (ranges::view <Views> && ...) && (sizeof...(Views) > 0)
class zip_view

    : public ranges::view_interface <zip_view<Views...>>
(1) (since C++23)
namespace views {

    inline constexpr /*unspecified*/ zip = /*unspecified*/;

}
(2) (since C++23)
Call signature
template< ranges::viewable_range... Rs >

    requires /* see below */

constexpr ranges::view auto zip( Rs&&... rs );
(since C++23)
1) zip_view is a range adaptor that takes one or more views, and produces a view whose ith element is a tuple-like value consisting of the ith elements of all views. The size of produced view is the minimum of sizes of all adapted views.
2) views::zip is a customization point object.

When calling with no argument, views::zip() is expression-equivalent to auto(views::empty <std::tuple <>>).

Otherwise, views::zip(rs...) is expression-equivalent to ranges::zip_view<views::all_t <decltype((rs))>...>(rs...).

zip_view always models input_range, and models forward_range, bidirectional_range, random_access_range, or sized_range if all adapted view types model the corresponding concept.

zip_view models common_range if

Customization point objects

The name views::zip denotes a customization point object, which is a const function object of a literal semiregular class type. See CustomizationPointObject for details.

[edit] Data members

Member Description
std::tuple <Views...> views_ all adapted view objects
(exposition-only member object*)

[edit] Member functions

constructs a zip_view
(public member function) [edit]
returns an iterator to the beginning
(public member function) [edit]
returns an iterator or a sentinel to the end
(public member function) [edit]
returns the number of elements, provided only if each underlying (adapted) range satisfies sized_range
(public member function) [edit]
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>) [edit]
(C++23)
returns a constant iterator to the beginning of the range
(public member function of std::ranges::view_interface<D>) [edit]
(C++23)
returns a sentinel for the constant iterator of the range
(public member function of std::ranges::view_interface<D>) [edit]
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>) [edit]
returns the first element in the derived view, provided if it satisfies forward_range
(public member function of std::ranges::view_interface<D>) [edit]
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>) [edit]
returns the nth element in the derived view, provided only if it satisfies random_access_range
(public member function of std::ranges::view_interface<D>) [edit]

[edit] Deduction guides

[edit] Nested classes

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

[edit] Helper templates

template< class... Views >

constexpr bool enable_borrowed_range<ranges::zip_view<Views...>> =

    (ranges::enable_borrowed_range <Views> && ...);
(since C++23)

This specialization of ranges::enable_borrowed_range makes zip_view satisfy borrowed_range when each underlying view satisfies it.

[edit] Notes

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

[edit] Example

Run this code
#include <array>
#include <iostream>
#include <list>
#include <ranges>
#include <string>
#include <tuple>
#include <vector>
 
void print(auto const rem, auto const& range)
{
 for (std::cout << rem; auto const& elem : range)
 std::cout << elem << ' ';
 std::cout << '\n';
}
 
int main()
{
 auto x = std::vector {1, 2, 3, 4};
 auto y = std::list <std::string >{"α", "β", "γ", "δ", "ε"};
 auto z = std::array {'A', 'B', 'C', 'D', 'E', 'F'};
 
 print("Source views:", "");
 print("x: ", x);
 print("y: ", y);
 print("z: ", z);
 
 print("\nzip(x,y,z):", "");
 
 for (std::tuple <int&, std::string &, char&> elem : std::views::zip(x, y, z))
 {
 std::cout << std::get<0>(elem) << ' '
 << std::get<1>(elem) << ' '
 << std::get<2>(elem) << '\n';
 
 std::get<char&>(elem) += ('a' - 'A'); // modifies the element of z
 }
 
 print("\nAfter modification, z: ", z);
}

Output:

Source views:
x: 1 2 3 4
y: α β γ δ ε
z: A B C D E F
 
zip(x,y,z):
1 α A
2 β B
3 γ C
4 δ D
 
After modification, z: a b c d E F

[edit] See also

a view consisting of results of application of a transformation function to corresponding elements of the adapted views
(class template) (customization point object)[edit]
takes a view consisting of tuple-like values and a number N and produces a view of Nth element of each tuple
(class template) (range adaptor object)[edit]

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