Defined in header <ranges> | ||
|---|---|---|
template< ranges::view V, class Pred >
requires ranges::input_range<V> &&
std::is_object_v<Pred> &&
std::indirect_unary_predicate<const Pred, ranges::iterator_t<V>>
class take_while_view :
public ranges::view_interface<take_while_view<V, Pred>>
| (1) | (since C++20) |
namespace views {
inline constexpr /*unspecified*/ take_while = /*unspecified*/;
}
| (2) | (since C++20) |
| Call signature | ||
template< ranges::viewable_range R, class Pred >
requires /* see below */
constexpr ranges::view auto take_while( R&& r, Pred&& pred );
| (since C++20) | |
template< class Pred > constexpr /*range adaptor closure*/ take_while( Pred&& pred ); | (since C++20) |
view of the elements from an underlying sequence, starting at the beginning and ending at the first element for which the predicate returns false.views::take_while(e, f) is expression-equivalent to take_while_view(e, f) for any suitable subexpressions e and f.take_while_view models the concepts contiguous_range, random_access_range, bidirectional_range, forward_range, and input_range when the underlying view V models respective concepts.
|
(C++20) | constructs a take_while_view (public member function) |
|
(C++20) | returns a copy of the underlying (adapted) view (public member function) |
|
(C++20) | returns a reference to the stored predicate (public member function) |
|
(C++20) | returns an iterator to the beginning (public member function) |
|
(C++20) | returns a sentinel representing the end (public member function) |
Inherited from |
|
|
(C++20) | returns whether the derived view is empty. Provided if it satisfies sized_range or forward_range. (public member function of std::ranges::view_interface<D>) |
|
(C++23) | returns a constant iterator to the beginning of the range. (public member function of std::ranges::view_interface<D>) |
|
(C++23) | returns a sentinel for the constant iterator of the range. (public member function of std::ranges::view_interface<D>) |
|
(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>) |
|
(C++20) | gets the address of derived view's data. Provided if its iterator type satisfies contiguous_iterator. (public member function of std::ranges::view_interface<D>) |
|
(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>) |
|
(C++20) | returns the nth element in the derived view. Provided if it satisfies random_access_range. (public member function of std::ranges::view_interface<D>) |
| the sentinel type (exposition-only member class template) |
#include <ranges>
#include <iostream>
int main()
{
for (int year : std::views::iota(2020)
| std::views::take_while([](int y) { return y <= 2023; }))
std::cout << year << ' ';
std::cout << '\n';
const char idea[] {"Today is yesterday's tomorrow!..."};
for (char x : std::ranges::take_while_view(idea, [](char c) { return c != '.'; }))
std::cout << x;
std::cout << '\n';
}Output:
2020 2021 2022 2023 Today is yesterday's tomorrow!
|
(C++20) | a view consisting of the first N elements of another view (class template) (range adaptor object) |
|
(C++20) | a view consisting of the elements of another view, skipping the initial subsequence of elements until the first element where the predicate returns false (class template) (range adaptor object) |
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