std::ranges::split_view<V,Pattern>::begin

 

C++

Compiler support

Freestanding and hosted

Language

Standard library

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_trange_value_trange_reference_t	iterator_tconst_iterator_tsentinel_tconst_sentinel_t (C++23)(C++23)	range_const_reference_trange_rvalue_reference_trange_common_reference_t (C++23)	elements_of (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
Range factories
empty_viewviews::empty single_viewviews::single	iota_viewviews::iota repeat_viewviews::repeat (C++23)(C++23)	basic_istream_viewviews::istream
Range adaptors
views::all_tviews::all ref_view owning_view as_rvalue_viewviews::as_rvalue (C++23)(C++23) filter_viewviews::filter transform_viewviews::transform take_viewviews::take take_while_viewviews::take_while	drop_viewviews::drop drop_while_viewviews::drop_while join_viewviews::join join_with_viewviews::join_with (C++23)(C++23) lazy_split_viewviews::lazy_split split_viewviews::split views::counted common_viewviews::common	reverse_viewviews::reverse as_const_viewviews::as_const (C++23)(C++23) elements_viewviews::elements keys_viewviews::keys values_viewviews::values enumerate_viewviews::enumerate (C++23)(C++23) zip_viewviews::zip (C++23)(C++23) zip_transform_viewviews::zip_transform (C++23)(C++23)	adjacent_viewviews::adjacent (C++23)(C++23) views::pairwise (C++23) adjacent_transform_viewviews::adjacent_transform (C++23)(C++23) views::pairwise_transform (C++23) chunk_viewviews::chunk (C++23)(C++23) slide_viewviews::slide (C++23)(C++23) chunk_by_viewviews::chunk_by (C++23)(C++23) stride_viewviews::stride (C++23)(C++23) cartesian_product_viewviews::cartesian_product (C++23)(C++23)
Range generators
std::generator (C++23)
Range adaptor objects
Range adaptor closure objects
range_adaptor_closure (C++23)
Helper items
copyable-box movable-box (until C++23)(C++23)	simple-view non-propagating-cache

 

std::ranges::split_view

Member functions

split_view::split_view (C++20)

split_view::base (C++20)

split_view::begin (C++20)

split_view::end (C++20)

split_view::find_next (C++20)

Nested classes

split_view::iterator (C++20)

split_view::sentinel (C++20)

Deduction guides

 

constexpr /*iterator*/ begin();		(since C++20)

Returns an iterator to the first found subrange.

In order to provide the amortized constant time complexity required by the range concept, this function caches the result within the split_view for use on subsequent calls. Equivalent to

constexpr /*iterator*/ begin()
{
    if (!cached_begin_.has_value())
        cached_begin_ = this->find_next(ranges::begin(base_));
    return { *this, ranges::begin(base_), cached_begin_.value() };
}

Exposition only data members base_ and cached_begin_ are described here.

Parameters

(none)

Return value

An iterator.

Complexity

Amortized \(\scriptsize \mathcal{O}(1)\)O(1).

Example

Run this code

#include <iostream>
#include <iomanip>
#include <ranges>
#include <string_view>
 
int main()
{
    constexpr std::string_view sentence{ "Keep..moving..forward.." };
    constexpr std::string_view delim{ ".." };
    std::ranges::split_view words{ sentence, delim };
 
    std::cout << "begin(): " << std::quoted( std::string_view{*words.begin()} )
              << "\nSubstrings: ";
    for (std::string_view word: words)
        std::cout << std::quoted(word) << ' ';
 
    std::ranges::split_view letters{ sentence, std::string_view{""} };
    std::cout << "\nbegin(): " << std::quoted( std::string_view{*letters.begin()} )
              << "\nLetters: ";
    for (std::string_view letter: letters)
        std::cout << letter << ' ';
}

Output:

begin(): "Keep"
Substrings: "Keep" "moving" "forward" ""
begin(): "K"
Letters: K e e p . . m o v i n g . . f o r w a r d . .

See also

end (C++20)	returns an iterator or a sentinel to the end (public member function)
begin (C++20)	returns an iterator to the beginning (public member function of std::ranges::lazy_split_view<V,Pattern>)
ranges::begin (C++20)	returns an iterator to the beginning of a range (customization point object)