std::ranges:: views::transform, std::ranges::
Defined in header <ranges>
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template
<
ranges::input_range V,
std::copy_constructible F >
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(since C++20) (until C++23) |
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template
<
ranges::input_range V,
std::move_constructible F >
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(since C++23) | |
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namespace views {
inline constexpr /*unspecified*/ transform = /*unspecified*/; |
(2) | (since C++20) |
Call signature |
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template
<
ranges::viewable_range R, class F >
requires /* see below */ |
(since C++20) | |
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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.
transform_view models the concepts random_access_range, bidirectional_range, forward_range, input_range, common_range, and sized_range when the underlying view V
Data members
| Member name | Definition |
base_ (private)
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the underlying view of type V
(exposition-only member object* |
fun_ (private)
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the underlying function object of type
copyable-box<F>
(until C++23)
movable-box<F>
(since C++23)
(exposition-only member object* |
Member functions
constructs a transform_view (public member function) |
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| returns a copy of the underlying (adapted) view (public member function) |
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| returns an iterator to the beginning (public member function) |
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| returns an iterator or a sentinel to the end (public member function) |
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returns the number of elements. Provided only if the underlying (adapted) range satisfies sized_range. (public member function) |
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Inherited from std::ranges::view_interface |
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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>)
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(C++23)
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returns a constant iterator to the beginning of the range. (public member function of std::ranges::view_interface<D>) |
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(C++23)
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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>)
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returns the first element in the derived view. Provided if it satisfies forward_range. (public member function of std::ranges::view_interface<D>)
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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>)
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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>)
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Deduction guides
Nested classes
| the iterator type (exposition-only member class template* |
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| the sentinel type (exposition-only member class template* |
Example
#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
See also
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(C++20)
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applies a function to a range of elements (algorithm function object) |