std::ranges::transform_view<V,F>::size

 

C++

Compiler support

Freestanding and hosted

Language

Standard library headers

Named requirements

Feature test macros (C++20)

Language support library

Concepts library (C++20)

Metaprogramming library (C++11)

Diagnostics library

General utilities library

Strings library

Containers library

Iterators library

Ranges library (C++20)

Algorithms library

Numerics library

Localizations library

Input/output library

Filesystem library (C++17)

Regular expressions library (C++11)

Concurrency support library (C++11)

Technical specifications

Symbols index

External libraries

 

Ranges library

Range access
begin cbegin end cend	rbegin crbegin rend crend	size ssize data cdata	empty
Range conversions
to (C++23)
Range primitives
range_size_trange_difference_t range_value_t	range_reference_trange_const_reference_trange_rvalue_reference_t   (C++23)	iterator_tconst_iterator_tsentinel_t (C++23)
Dangling iterator handling
dangling	borrowed_iterator_t	borrowed_subrange_t
Range concepts
range borrowed_range    sized_range constant_range (C++23)	common_range view viewable_range	input_range output_range forward_range	bidirectional_range random_access_range contiguous_range
Views
view_interface	subrange
Factories
empty_viewviews::empty iota_viewviews::iota	single_viewviews::single basic_istream_viewviews::istream	repeat_viewviews::repeat (C++23)(C++23)
Adaptors
ref_view views::all_tviews::all common_viewviews::common owning_view views::counted reverse_viewviews::reverse zip_viewviews::zip (C++23)(C++23) as_const_viewviews::as_const (C++23)(C++23) as_rvalue_viewviews::as_rvalue (C++23)(C++23)	take_viewviews::take take_while_viewviews::take_while drop_viewviews::drop drop_while_viewviews::drop_while zip_transform_viewviews::zip_transform (C++23)(C++23) adjacent_transform_viewviews::adjacent_transform (C++23)(C++23)   cartesian_product_viewviews::cartesian_product (C++23)(C++23)	elements_viewviews::elements keys_viewviews::keys values_viewviews::values transform_viewviews::transform adjacent_viewviews::adjacent (C++23)(C++23) slide_viewviews::slide (C++23)(C++23) stride_viewviews::stride (C++23)(C++23)	filter_viewviews::filter join_viewviews::join split_viewviews::split lazy_split_viewviews::lazy_split join_with_viewviews::join_with (C++23)(C++23) chunk_viewviews::chunk (C++23)(C++23) chunk_by_viewviews::chunk_by (C++23)(C++23)
Range adaptor objects
Range adaptor closure objects
Helper items
copyable-box	simple-view

 

std::ranges::transform_view

Member functions

transform_view::transform_view (C++20)

transform_view::base (C++20)

transform_view::begin (C++20)

transform_view::end (C++20)

transform_view::size (C++20)

Deduction guides

Iterator

transform_view::iterator::iterator (C++20)

transform_view::iterator::base (C++20)

transform_view::iterator::operator* (C++20)

transform_view::iterator::operator[] (C++20)

transform_view::iterator::operator++ transform_view::iterator::operator++(int) transform_view::iterator::operator-- transform_view::iterator::operator--(int) transform_view::iterator::operator+= transform_view::iterator::operator-= (C++20)(C++20)(C++20)(C++20)(C++20)(C++20)

operator==(transform_view::iterator) operator<(transform_view::iterator) operator>(transform_view::iterator) operator<=(transform_view::iterator) operator>=(transform_view::iterator) operator<=>(transform_view::iterator) (C++20)(C++20)(C++20)(C++20)(C++20)(C++20)

operator+(transform_view::iterator) operator-(transform_view::iterator) (C++20)(C++20)

iter_move(transform_view::iterator) (C++20)

Sentinel

transform_view::sentinel::sentinel (C++20)

transform_view::sentinel::base (C++20)

operator==(transform_view::iterator,transform_view::sentinel) (C++20)

operator-(transform_view::iterator,transform_view::sentinel) (C++20)

 

constexpr auto size() requires ranges::sized_range<V>;		(since C++20)
constexpr auto size() const requires ranges::sized_range<const V>;		(since C++20)

Returns the number of elements.

Returns ranges::size(base_), where base_ is the underlying view.

Parameters

(none)

Return value

The number of elements.

Notes

If V does not model forward_range, size() might not be well-defined after a call to begin().

Example

Run this code

#include <iostream>
#include <ranges>
#include <string>
#include <cctype>
 
int main()
{
    std::string s{"The length of this string is 42 characters"};
    auto tv = std::ranges::transform_view{s, [](char c) -> char {
        return std::toupper(c); }
    };
    for (auto x: tv) { std::cout << x; };
    std::cout << "\nsize = " << tv.size() << '\n';
}

Output:

THE LENGTH OF THIS STRING IS 42 CHARACTERS
size = 42

See also

ranges::size (C++20)	returns an integer equal to the size of a range (customization point object)
ranges::ssize (C++20)	returns a signed integer equal to the size of a range (customization point object)