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

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.

Member functions

Deduction guides

Member types

Data members

Nested classes

Notes

Example

#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);
}

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

See also