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std::ranges::views::drop, std::ranges::drop_view

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Revision as of 18:53, 2 June 2020 by D41D8CD98F (Talk | contribs)

 
 
Ranges library
Range adaptors
 
 
template< ranges::view V >
class drop_view : public ranges::view_interface<drop_view<V>>
(1) (since C++20)
namespace views {

    inline constexpr /*unspecified*/ drop = /*unspecified*/;

}
(2) (since C++20)
1) A range adaptor consisting of elements of the underlying sequence, skipping the first N elements.
2) The expression views::drop(E,F) is expression-equivalent to (where T is std::remove_cvref_t<decltype((E))> and D is ranges::range_difference_t<decltype((E))>):
  • std::span where T::extent == std::dynamic_extent,
  • std::basic_string_view,
  • ranges::iota_view, or
  • ranges::subrange;
  • otherwise, drop_view{E, F}.
In all cases, decltype((F)) must model std::convertible_to<D>.

drop_view models the concepts contiguous_range, random_access_range, bidirectional_range, forward_range, input_range, and common_range when the underlying view V models respective concepts.

Contents

Expression-equivalent

Expression e is expression-equivalent to expression f, if

  • e and f have the same effects, and
  • either both are constant subexpressions or else neither is a constant subexpression, and
  • either both are potentially-throwing or else neither is potentially-throwing (i.e. noexcept(e) == noexcept(f)).

Member functions

constructs a drop_view
(public member function) [edit]
returns a copy of the underlying (adapted) view
(public member function) [edit]
returns an iterator to the beginning
(public member function) [edit]
returns an iterator or a sentinel to the end
(public member function) [edit]
returns the number of elements. Provided only if the underlying (adapted) range satisfies sized_range.
(public member function) [edit]

Deduction guides

Example