[range.split.view]

# 25 Ranges library [[ranges]](./#ranges)

## 25.7 Range adaptors [[range.adaptors]](range.adaptors#range.split.view)

### 25.7.17 Split view [[range.split]](range.split#view)

#### 25.7.17.2 Class template split_view [range.split.view]

[ð](#lib:split_view)

namespace std::ranges {template<[forward_range](range.refinements#concept:forward_range "25.4.6 Other range refinements [range.refinements]") V, [forward_range](range.refinements#concept:forward_range "25.4.6 Other range refinements [range.refinements]") Pattern>requires [view](range.view#concept:view "25.4.5 Views [range.view]")<V> && [view](range.view#concept:view "25.4.5 Views [range.view]")<Pattern> &&[indirectly_comparable](alg.req.ind.cmp#concept:indirectly_comparable "24.3.7.5 Concept indirectly_­comparable [alg.req.ind.cmp]")<iterator_t<V>, iterator_t<Pattern>, ranges::equal_to>class split_view : public view_interface<split_view<V, Pattern>> {private: V *base_* = V(); // *exposition only* Pattern *pattern_* = Pattern(); // *exposition only*// [[range.split.iterator]](range.split.iterator "25.7.17.3 Class split_­view​::​iterator"), class split_view​::​*iterator*struct *iterator*; // *exposition only*// [[range.split.sentinel]](range.split.sentinel "25.7.17.4 Class split_­view​::​sentinel"), class split_view​::​*sentinel*struct *sentinel*; // *exposition only*public: split_view()requires [default_initializable](concept.default.init#concept:default_initializable "18.4.12 Concept default_­initializable [concept.default.init]")<V> && [default_initializable](concept.default.init#concept:default_initializable "18.4.12 Concept default_­initializable [concept.default.init]")<Pattern> = default; constexpr explicit split_view(V base, Pattern pattern); template<[forward_range](range.refinements#concept:forward_range "25.4.6 Other range refinements [range.refinements]") R>requires [constructible_from](concept.constructible#concept:constructible_from "18.4.11 Concept constructible_­from [concept.constructible]")<V, views::all_t<R>> &&[constructible_from](concept.constructible#concept:constructible_from "18.4.11 Concept constructible_­from [concept.constructible]")<Pattern, single_view<range_value_t<R>>>constexpr explicit split_view(R&& r, range_value_t<R> e); constexpr V base() const & requires [copy_constructible](concept.copyconstructible#concept:copy_constructible "18.4.14 Concept copy_­constructible [concept.copyconstructible]")<V> { return *base_*; }constexpr V base() && { return std::move(*base_*); }constexpr *iterator* begin(); constexpr auto end() {if constexpr ([common_range](range.refinements#concept:common_range "25.4.6 Other range refinements [range.refinements]")<V>) {return *iterator*{*this, ranges::end(*base_*), {}}; } else {return *sentinel*{*this}; }}constexpr subrange<iterator_t<V>> *find-next*(iterator_t<V>); // *exposition only*}; template<class R, class P> split_view(R&&, P&&) -> split_view<views::all_t<R>, views::all_t<P>>; template<[forward_range](range.refinements#concept:forward_range "25.4.6 Other range refinements [range.refinements]") R> split_view(R&&, range_value_t<R>)-> split_view<views::all_t<R>, single_view<range_value_t<R>>>;}

[ð](#lib:split_view,constructor)

`constexpr explicit split_view(V base, Pattern pattern);
`

[1](#1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/ranges.tex#L8466)

*Effects*: Initializes *base_* with std​::​move(base), and*pattern_* with std​::​move(pattern)[.](#1.sentence-1)

[ð](#lib:split_view,constructor_)

`template<[forward_range](range.refinements#concept:forward_range "25.4.6 Other range refinements [range.refinements]") R>
  requires [constructible_from](concept.constructible#concept:constructible_from "18.4.11 Concept constructible_­from [concept.constructible]")<V, views::all_t<R>> &&
           [constructible_from](concept.constructible#concept:constructible_from "18.4.11 Concept constructible_­from [concept.constructible]")<Pattern, single_view<range_value_t<R>>>
constexpr explicit split_view(R&& r, range_value_t<R> e);
`

[2](#2)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/ranges.tex#L8481)

*Effects*: Initializes *base_* with views​::​all(std​::​forward<R>(r)), and*pattern_* with views​::​single(std​::​move(e))[.](#2.sentence-1)

[ð](#lib:begin,split_view)

`constexpr iterator begin();
`

[3](#3)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/ranges.tex#L8493)

*Returns*: {*this, ranges​::​begin(*base_*), *find-next*(ranges​::​begin(*base_*))}[.](#3.sentence-1)

[4](#4)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/ranges.tex#L8497)

*Remarks*: In order to provide the amortized constant time complexity
required by the [range](range.range#concept:range "25.4.2 Ranges [range.range]") concept,
this function caches the result within the split_view for use on subsequent calls[.](#4.sentence-1)

[ð](#lib:find-next,split_view)

`constexpr subrange<iterator_t<V>> find-next(iterator_t<V> it);
`

[5](#5)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/ranges.tex#L8511)

*Effects*: Equivalent to:auto [b, e] = ranges::search(subrange(it, ranges::end(*base_*)), *pattern_*);if (b != ranges::end(*base_*) && ranges::empty(*pattern_*)) {++b; ++e;}return {b, e};
