std::ranges::views::lazy_split, std::ranges::lazy_split_view

 

C++

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Named requirements

Language support library

Concepts library (C++20)

Diagnostics library

Utilities library

Strings library

Containers library

Iterators library

Ranges library (C++20)

Algorithms library

Numerics library

Localizations library

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Filesystem library (C++17)

Regular expressions library (C++11)

Atomic operations library (C++11)

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Technical Specifications

 

Ranges library

Range access
begin cbegin end cend	rbegin crbegin rend crend	size ssize data cdata	empty
Range primitives
iterator_tsentinel_t	range_size_trange_difference_t	range_reference_trange_rvalue_reference_t	range_value_t
Dangling iterator handling
dangling	borrowed_iterator_t	borrowed_subrange_t
Range concepts
range borrowed_range    sized_range	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	single_viewviews::single	iota_viewviews::iota	basic_istream_viewistream_view
Adaptors
views::all_tviews::all common_viewviews::common filter_viewviews::filter reverse_viewviews::reverse	take_viewviews::take take_while_viewviews::take_while drop_viewviews::drop drop_while_viewviews::drop_while	elements_viewviews::elements keys_viewviews::keys values_viewviews::values transform_viewviews::transform	join_viewviews::join split_viewviews::split lazy_split_viewviews::lazy_split ref_view views::counted
Range adaptor objects
Range adaptor closure objects
Helper items
copyable-box	simple-view	different-from

 

std::ranges::lazy_split_view

Member functions

lazy_split_view::lazy_split_view

lazy_split_view::base

lazy_split_view::begin

lazy_split_view::end

Nested classes

lazy_split_view::inner_iterator

lazy_split_view::outer_iterator

Deduction guides

 

Defined in header <ranges>
template< ranges::input_range V, ranges::forward_range Pattern > requires ranges::view<V> && ranges::view<Pattern> &&   std::indirectly_comparable<ranges::iterator_t<V>, ranges::iterator_t<Pattern>,                              ranges::equal_to> &&   (ranges::forward_range<V> || /*tiny-range*/<Pattern>) class lazy_split_view : public ranges::view_interface<lazy_split_view<V, Pattern>>	(1)	(since C++20)
namespace views {     inline constexpr /*unspecified*/ lazy_split = /*unspecified*/; }	(2)	(since C++20)

1) lazy_split_view takes a view and a delimiter, and splits the view into subranges on the delimiter.

Two major scenarios are supported:

• The view is a input_range, the delimiter is a single element (wrapped in a single_view).
• The view is a forward_range, the delimiter is a view of elements.

The exposition-only concept /*tiny-range*/<Pattern> is satisfied if Pattern satisfies sized_range, Pattern::size() is a constant expression, and the value of Pattern::size() is less than or equal to 1. Notably, empty_view and single_view satisfy this concept.

2) A range adaptor object. The expression views::lazy_split(e, f) is expression-equivalent to lazy_split_view(e, f).

Member functions

(constructor) (C++20)	constructs a lazy_split_view (public member function)
base (C++20)	returns a copy of the underlying (adapted) view (public member function)
begin (C++20)	returns an iterator to the beginning (public member function)
end (C++20)	returns an iterator or a sentinel to the end (public member function)
Inherited from std::ranges::view_interface
empty (C++20)	Returns whether the derived view is empty. Provided if it satisfies forward_range. (public member function of std::ranges::view_interface<D>)
operator bool (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>)
front (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>)

Nested classes

outer_iterator	the iterator type (public member class)
inner_iterator	the iterator type of the inner range (public member class)

Example

Run this code

#include <algorithm>
#include <iostream>
#include <ranges>
#include <string_view>
 
// P2210R2: a temporary patch until online g++ >= 12
#define lazy_split_view split_view
#define lazy_split split
 
auto print = [](auto const& view)
{
    // `view` is a std::views::lazy_split_view::/*outer-iterator*/::value_type
 
    for (std::cout << "{ "; const auto element : view)
        std::cout << element << ' ';
    std::cout << "} ";
};
 
int main()
{
    constexpr static auto source = { 0, 1,0, 2,3,0, 4,5,6,0, 7,8,9 };
    constexpr int delimiter {0};
    constexpr std::ranges::lazy_split_view lazy_split_view {source, delimiter};
    std::cout << "splits[" << std::ranges::distance(lazy_split_view) << "]:  ";
    for (auto const& lazy_split: lazy_split_view)
        print(lazy_split);
 
    constexpr std::string_view hello { "Hello C++ 20 !" };
    std::cout << "\n" "substrings: ";
    std::ranges::for_each(hello | std::views::lazy_split(' '), print);
 
    constexpr std::string_view text { "Hello-+-C++-+-20-+-!" };
    constexpr std::string_view delim { "-+-" };
    std::cout << "\n" "substrings: ";
    std::ranges::for_each(text | std::views::lazy_split(delim), print);
}

Output:

splits[5]:  { } { 1 } { 2 3 } { 4 5 6 } { 7 8 9 } 
substrings: { H e l l o } { C + + } { 2 0 } { ! }
substrings: { H e l l o } { C + + } { 2 0 } { ! }

See also

ranges::split_viewviews::split (C++20)	a view over the subranges obtained from splitting another view using a delimiter (class template) (range adaptor object)
ranges::join_viewviews::join (C++20)	a view consisting of the sequence obtained from flattening a view of ranges (class template) (range adaptor object)