std::ranges::views::split, std::ranges::split_view - cppreference.com (original) (raw)
| Defined in header | ||
|---|---|---|
| template< ranges::forward_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> class split_view : public ranges::view_interface<split_view<V, Pattern>> | (1) | (since C++20) |
| namespace views { inline constexpr /* unspecified */ split = /* unspecified */; } | (2) | (since C++20) |
| Call signature | ||
| template< ranges::viewable_range R, class Pattern > requires /* see below */ constexpr ranges::view auto split( R&& r, Pattern&& pattern ); | (since C++20) | |
| template< class Pattern > constexpr /* range adaptor closure */ split( Pattern&& pattern ); | (since C++20) |
split_view models the concepts forward_range, and common_range when the underlying view V models respective concepts.
The inner range (ranges::range_reference_t<split_view>) is a ranges::subrange<ranges::iterator_t<V>>, which models common_range, models sized_range when ranges::iterator_t<V> models std::sized_sentinel_for<ranges::iterator_t<V>>, and models contiguous_range, random_access_range, bidirectional_range, and forward_range when V models respective concepts.
Unlike lazy_split_view, split_view maintains the continuity of the subrange, making it suitable for string splitting.
Contents
- 1 Data members
- 2 Member functions
- 3 Nested classes
- 4 Deduction guides
- 5 Notes
- 6 Example
- 7 Defect reports
- 8 See also
[edit] Data members
| Member | Description |
|---|---|
| V base_ (private) | the underlying (adapted) view(exposition-only member object*) |
| Pattern pattern_ (private) | the pattern object that is used as a delimiter to split the underlying view(exposition-only member object*) |
| non-propagating-cache<ranges::subrange <ranges::iterator_t<V>>> cached_begin_ (private) | an object that caches the result of the first call to begin()(exposition-only member object*) |
[edit] Member functions
| (constructor) | constructs a split_view (public member function) [edit] |
|---|---|
| base | returns a copy of the underlying (adapted) view (public member function) [edit] |
| begin | returns an iterator to the beginning (public member function) [edit] |
| end | returns an iterator or a sentinel to the end (public member function) [edit] |
| find_next | searches for the next occurrence of the pattern(exposition-only member function*) |
| Inherited from std::ranges::view_interface | |
| empty | returns whether the derived view is empty, provided only if it satisfies sized_range or forward_range (public member function of std::ranges::view_interface) [edit] |
| cbegin(C++23) | returns a constant iterator to the beginning of the range (public member function of std::ranges::view_interface) [edit] |
| cend(C++23) | returns a sentinel for the constant iterator of the range (public member function of std::ranges::view_interface) [edit] |
| operator bool | returns whether the derived view is not empty, provided only if ranges::empty is applicable to it (public member function of std::ranges::view_interface) [edit] |
| front | returns the first element in the derived view, provided if it satisfies forward_range (public member function of std::ranges::view_interface) [edit] |
[edit] Nested classes
| | the iterator type(exposition-only member class*) | | ---------------------------------------------------- | | | the sentinel type(exposition-only member class*) |
[edit] Deduction guides
[edit] Notes
Before P2210R2, split_view used a lazy mechanism for splitting, and thus could not keep the bidirectional, random access, or contiguous properties of the underlying view, or make the iterator type of the inner range same as that of the underlying view. Consequently, it is redesigned by P2210R2, and the lazy mechanism is moved to lazy_split_view.
The delimiter pattern generally should not be an ordinary string literal, as it will consider the null terminator to be necessary part of the delimiter; therefore, it is advisable to use a std::string_view literal instead.
[edit] Example
#include #include #include #include int main() { using std::operator""sv; constexpr auto words{"Hello^_^C++^_^20^_^!"sv}; constexpr auto delim{"^_^"sv}; for (const auto word : std::views::split(words, delim)) // with string_view's C++23 range constructor: std::cout << std::quoted(std::string_view(word)) << ' '; std::cout << '\n'; }
Output:
[edit] Defect reports
The following behavior-changing defect reports were applied retroactively to previously published C++ standards.
| DR | Applied to | Behavior as published | Correct behavior |
|---|---|---|---|
| P2210R2 | C++20 | the old split_view was too lazy to be easily used | it is redesigned |