Defined in header <ranges> | ||
|---|---|---|
template< ranges::input_range V,
std::copy_constructible F >
requires ranges::view<V> and
std::is_object_v<F> and
std::regular_invocable<F&, ranges::range_reference_t<V>> and
/* invoke_result_t<F&, range_reference_t<V>>& is a valid type */
class transform_view :
public ranges::view_interface<transform_view<V, F>>
| (1) | (since C++20) |
namespace views {
inline constexpr /*unspecified*/ transform = /*unspecified*/;
}
| (2) | (since C++20) |
| Call signature | ||
template< ranges::viewable_range R, class F >
requires /* see below */
constexpr ranges::view auto transform( R&& r, F&& fun );
| (since C++20) | |
template< class F > constexpr /*range adaptor closure*/ transform( F&& fun ); | (since C++20) |
view of an underlying sequence after applying a transformation function to each element.views::transform(e, f) is expression-equivalent to transform_view(e, f) for any suitable subexpressions e and f.transform_view models the concepts random_access_range, bidirectional_range, forward_range, input_range, common_range, and sized_range when the underlying view V models respective concepts.
|
(C++20) | constructs a transform_view (public member function) |
|
(C++20) | returns a copy of the underlying (adapted) view (public member function) |
|
(C++20) | returns an iterator to the beginning (public member function) |
|
(C++20) | returns an iterator or a sentinel to the end (public member function) |
|
(C++20) | returns the number of elements. Provided only if the underlying (adapted) range satisfies sized_range. (public member function) |
Inherited from |
|
|
(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>) |
|
(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>) |
|
(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>) |
|
(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>) |
|
(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>) |
|
(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>) |
|
(C++20) | the iterator type (exposition-only member class template) |
|
(C++20) | the sentinel type (exposition-only member class template) |
#include <algorithm>
#include <cstdio>
#include <iterator>
#include <ranges>
#include <string>
char rot13a(const char x, const char a)
{
return a + (x - a + 13) % 26;
}
char rot13(const char x)
{
if ('Z' >= x and x >= 'A')
return rot13a(x, 'A');
if ('z' >= x and x >= 'a')
return rot13a(x, 'a');
return x;
}
int main()
{
auto show = [](const unsigned char x) { std::putchar(x); };
std::string in{ "cppreference.com\n" };
std::ranges::for_each(in, show);
std::ranges::for_each(in | std::views::transform(rot13), show);
std::string out;
std::ranges::copy(std::views::transform(in, rot13), std::back_inserter(out));
std::ranges::for_each(out, show);
std::ranges::for_each(out | std::views::transform(rot13), show);
}Output:
cppreference.com pccersrerapr.pbz pccersrerapr.pbz cppreference.com
|
(C++20) | applies a function to a range of elements (niebloid) |
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https://en.cppreference.com/w/cpp/ranges/transform_view