ranges::views::transform_fn Struct Reference

#include <range/v3/view/transform.hpp>

Inheritance diagram for ranges::views::transform_fn:

Public Member Functions
template<typename Fun >
constexpr auto	operator() (Fun fun) const
Public Member Functions inherited from ranges::views::transform_base_fn
template<typename Rng , typename Fun > requires transformable_range<Rng, Fun>
constexpr transform_view< all_t< Rng >, Fun >	operator() (Rng &&rng, Fun fun) const
template<typename Rng1 , typename Rng2 , typename Fun > requires transformable_ranges<Rng1, Rng2, Fun>
constexpr transform2_view< all_t< Rng1 >, all_t< Rng2 >, Fun >	operator() (Rng1 &&rng1, Rng2 &&rng2, Fun fun) const

Related Functions
(Note that these are not member functions.)
constexpr transform_fn	transform {}

Detailed Description

ranges::views::transform

The transform view takes in a function T -> U and converts an input range of T into an output range of U by calling the function on every element of the input range.

Example

#include <iostream>
#include <vector>
#include <range/v3/view/transform.hpp>
 
int main()
{
    std::vector<int> numbers{1, 2, 3};
 
    auto halved = numbers
        // Divide each integer by 2, converting it into a double
        | ranges::views::transform([](const int& num) {
          return num / 2.0;
        });
 
    std::cout << halved << '\n';
}

Output

[0.5,1,1.5]

Syntax

auto output_range = input_range | ranges::views::transform(transform_func);

Parameters

transform_func

• Maps an input value to an output value (transform_func(T) -> U)

input_range

• The range of elements to transform
• Reference type: T

output_range

• The range of output values
• Reference type: U
• Value type: decay_t<U>
• This range will have the same category as the input range (excluding contiguous ranges). Contiguous ranges are reduced to random access ranges.