std::ranges:: views:: transform, std::ranges:: transform_view
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Defined in header
<ranges>
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||
| (1) | ||
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template
<
ranges::
input_range
V,
std::
copy_constructible
F
>
|
(since C++20)
(until C++23) |
|
|
template
<
ranges::
input_range
V,
std::
move_constructible
F
>
|
(since C++23) | |
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namespace
views
{
inline
constexpr
/*unspecified*/
transform
=
/*unspecified*/
;
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(2) | (since C++20) |
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Call signature
|
||
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template
<
ranges::
viewable_range
R,
class
F
>
requires
/* see below */
|
(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.
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.
Data members
| Member name | Definition |
base_
(private)
|
the underlying
view
of type
V
( exposition-only member object* ) |
fun_
(private)
|
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) |
|
|
returns a copy of the underlying (adapted) 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 the underlying (adapted) range satisfies
sized_range
.
(public member function) |
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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>
)
|
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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
( 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
|
(C++20)
|
applies a function to a range of elements
(algorithm function object) |