std::ranges::zip_view<Views...>::size
From cppreference.com
C++
Ranges library
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std::ranges::zip_view
| Member functions | ||||
zip_view::size | ||||
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constexpr
auto size(
)
requires ( ranges::sized_range <Views> && ...) ; |
(1) | (since C++23) |
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constexpr
auto size(
)
const
requires ( ranges::sized_range < const Views> && ...) ; |
(2) | (since C++23) |
Returns the number of elements in the zip_view. Provided only if each underlying (adapted) range satisfies sized_range
Equivalent to:
return std::apply ( [](auto... sizes) { using CT = /*make-unsigned-like-t*/<std::common_type_t<decltype(sizes)...>>; return ranges::min({CT(sizes)...}); }, /*tuple-transform*/(ranges::size, views_) );
Parameters
(none)
Return value
The number of elements, which is the minimum size among all sizes of adapted views.
Example
Run this code
#include <algorithm> #include <cassert> #include <deque> #include <forward_list> #include <ranges> #include <vector> int main() { auto x = std::vector{1, 2, 3, 4, 5}; auto y = std::deque{'a', 'b', 'c'}; auto z = std::forward_list{1., 2.}; auto v1 = std::views::zip(x, y); assert(v1.size() == std::min(x.size(), y.size())); assert(v1.size() == 3); [[maybe_unused]] auto v2 = std::views::zip(x, z); // auto sz = v2.size(); // Error, v2 does not have size(): static_assert(not std::ranges::sized_range<decltype(z)>); }
See also
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(C++20)
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returns an integer equal to the size of a range (customization point object) |
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(C++20)
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returns a signed integer equal to the size of a range (customization point object) |