std::ranges:: views::zip, std::ranges::
Defined in header <ranges>
|
||
template
<
ranges::input_range... Views
>
requires (
ranges::view
<Views>
&& ...)
&&
(sizeof...(Views)
>
0
)
|
(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 */ |
(since C++23) | |
zip_view
is a range adaptor that takes one or more view
s, and produces a view
whose i
th element is a tuple-like value consisting of the i
th
views::zip
is a customization point object.When calling with no argument, views::zip() is expression-equivalent to
auto
(
views::empty
<
std::tuple
<>>
)
.
zip_view
always models input_range
, and models forward_range
, bidirectional_range
, random_access_range
, or sized_range
if all adapted view
zip_view
models common_range
if
-
sizeof...(Views) is equal to 1, and the only adapted view type models
common_range
- at least one adapted view type does not model
bidirectional_range
, and every adapted view type modelscommon_range
- every adapted view type models both
random_access_range
andsized_range
.
Customization point objects
The name views::zip
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_fn
All instances of __zip_fn
are equal. The effects of invoking different instances of type
__zip_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
Given a set of types Args...
, if
std::declval
<Args>
(
)
meet the requirements for arguments to views::zip
above, __zip_fn
models
- std::invocable<__zip_fn, Args...>
- std::invocable < const __zip_fn, Args...>
- std::invocable <__zip_fn&, Args...>
-
std::invocable
<
const __zip_fn&, Args...>
.
Otherwise, no function call operator of __zip_fn
participates in overload resolution.
Data members
Member | Description |
std::tuple<Views...>
views_
|
all adapted view objects (exposition-only member object* |
Member functions
constructs a zip_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) |
|
returns the number of elements. Provided only if each underlying (adapted) range satisfies sized_range . (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> )
|
|
returns the n
th element in the derived view. Provided if it satisfies random_access_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 used when zip_view is not a common_range
(exposition-only member class template* |
Helper templates
template
<
class... Views
>
constexpr
bool enable_borrowed_range<ranges::
zip_view
<Views...>>
=
|
(since C++23) | |
This specialization of ranges::enable_borrowed_range makes zip_view
satisfy borrowed_range
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 |
Example
#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
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) |
|
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) |