std::ranges::all_of, std::ranges::any_of, std::ranges::none_of
来自 zh.cppreference.net
| 定义于头文件 <algorithm>
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| 调用签名 |
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template< std::input_iterator I, std::sentinel_for<I> S,
class Proj = std::identity,
std::indirect_unary_predicate<std::projected<I, Proj>> Pred >
constexpr bool all_of( I first, S last, Pred pred, Proj proj = {} );
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(1) | (自C++20起) |
template< ranges::input_range R, class Proj = std::identity,
std::indirect_unary_predicate
<std::projected<ranges::iterator_t<R>, Proj>> Pred >
constexpr bool all_of( R&& r, Pred pred, Proj proj = {} );
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(2) | (自C++20起) |
template< std::input_iterator I, std::sentinel_for<I> S,
class Proj = std::identity,
std::indirect_unary_predicate<std::projected<I, Proj>> Pred >
constexpr bool any_of( I first, S last, Pred pred, Proj proj = {} );
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(3) | (自C++20起) |
template< ranges::input_range R, class Proj = std::identity,
std::indirect_unary_predicate
<std::projected<ranges::iterator_t<R>, Proj>> Pred >
constexpr bool any_of( R&& r, Pred pred, Proj proj = {} );
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(4) | (自C++20起) |
template< std::input_iterator I, std::sentinel_for<I> S,
class Proj = std::identity,
std::indirect_unary_predicate<std::projected<I, Proj>> Pred >
constexpr bool none_of( I first, S last, Pred pred, Proj proj = {} );
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(5) | (自C++20起) |
template< ranges::input_range R, class Proj = std::identity,
std::indirect_unary_predicate
<std::projected<ranges::iterator_t<R>, Proj>> Pred >
constexpr bool none_of( R&& r, Pred pred, Proj proj = {} );
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(6) | (自C++20起) |
template< /*execution-policy*/ Ep, std::random_access_iterator I,
std::sized_sentinel_for<I> S, class Proj = std::identity,
std::indirect_unary_predicate<std::projected<I, Proj>> Pred >
bool all_of( Ep&& policy, I first, S last, Pred pred, Proj proj = {} );
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(7) | (自C++26起) |
template< /*execution-policy*/ Ep,
/*sized-random-access-range*/ R, class Proj = std::identity,
std::indirect_unary_predicate
<std::projected<ranges::iterator_t<R>, Proj>> Pred >
bool all_of( Ep&& policy, R&& r, Pred pred, Proj proj = {} );
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(8) | (自C++26起) |
template< /*execution-policy*/ Ep, std::random_access_iterator I,
std::sized_sentinel_for<I> S, class Proj = std::identity,
std::indirect_unary_predicate<std::projected<I, Proj>> Pred >
bool any_of( Ep&& policy, I first, S last, Pred pred, Proj proj = {} );
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(9) | (自C++26起) |
template< /*execution-policy*/ Ep,
/*sized-random-access-range*/ R, class Proj = std::identity,
std::indirect_unary_predicate
<std::projected<ranges::iterator_t<R>, Proj>> Pred >
bool any_of( Ep&& policy, R&& r, Pred pred, Proj proj = {} );
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(10) | (自C++26起) |
template< /*execution-policy*/ Ep, std::random_access_iterator I,
std::sized_sentinel_for<I> S, class Proj = std::identity,
std::indirect_unary_predicate<std::projected<I, Proj>> Pred >
bool none_of( Ep&& policy, I first, S last, Pred pred, Proj proj = {} );
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(11) | (自C++26起) |
template< /*execution-policy*/ Ep,
/*sized-random-access-range*/ R, class Proj = std::identity,
std::indirect_unary_predicate
<std::projected<ranges::iterator_t<R>, Proj>> Pred >
bool none_of( Ep&& policy, R&& r, Pred pred, Proj proj = {} );
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(12) | (自C++26起) |
关于 /*execution-policy*/ 的定义，见此页面；关于 /*sized-random-access-range*/ 的定义，见此页面。
1,2) 检查一元谓词
pred 是否返回 false 对于至少一个元素（经 proj 投影后）在范围 [first, last) 或 r 中。3,4) 检查一元谓词
pred 是否返回 true 对于至少一个元素（经 proj 投影后）在范围 [first, last) 或 r 中。5,6) 检查一元谓词
pred 是否不返回 true 对于任何元素（经 proj 投影后）在范围 [first, last) 或 r 中。7-12) 同 (1-6)，但按照
policy 执行。此页面描述的函数式实体是算法函数对象（非正式地称为niebloids），即：
参数
| first, last | - | 定义要检查元素范围的迭代器-哨兵对 范围 |
| r | - | 要检查的元素范围 |
| pred | - | 要应用于（投影后）元素的谓词 |
| proj | - | 要应用于元素的投影 |
| policy | - | 要使用的执行策略 |
返回值
范围有 true 元素
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是 | 否 | ||
|---|---|---|---|---|
范围有 false 元素
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是 | 否 | 是 | 否[1] |
all_of
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false
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true
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false
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true
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any_of
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true
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true
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false
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false
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none_of
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false
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false
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true
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true
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- ↑ 此情况下范围为空。
复杂度
最多 range::distance(first, last) 或 range::distance(r) 次应用 pred 以及 proj。
异常
7-12)执行过程中：
- 如果并行化所需的临时内存资源不可用，std::bad_alloc则被抛出。
- 如果通过算法参数访问对象时抛出了未被捕获的异常，则行为由执行策略决定（对于标准策略，std::terminate会被调用）。
可能的实现
| all_of (1,2) |
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struct all_of_fn
{
template<std::input_iterator I, std::sentinel_for<I> S, class Proj = std::identity,
std::indirect_unary_predicate<std::projected<I, Proj>> Pred>
constexpr bool operator()(I first, S last, Pred pred, Proj proj = {}) const
{
return ranges::find_if_not(first, last, std::ref(pred), std::ref(proj)) == last;
}
template<ranges::input_range R, class Proj = std::identity,
std::indirect_unary_predicate
<std::projected<ranges::iterator_t<R>, Proj>> Pred>
constexpr bool operator()(R&& r, Pred pred, Proj proj = {}) const
{
return operator()(ranges::begin(r), ranges::end(r),
std::ref(pred), std::ref(proj));
}
template<ranges::forward_range R, class Proj = std::identity,
std::indirect_unary_predicate
<std::projected<ranges::iterator_t<R>, Proj>> Pred>
constexpr bool operator()(R&& r, Pred pred, Proj proj = {}) const
{
return operator()(ranges::begin(r),
ranges::next(ranges::begin(r), ranges::end(r)),
std::ref(pred), std::ref(proj));
}
};
inline constexpr all_of_fn all_of;
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| any_of (3,4) |
struct any_of_fn
{
template<std::input_iterator I, std::sentinel_for<I> S, class Proj = std::identity,
std::indirect_unary_predicate<std::projected<I, Proj>> Pred>
constexpr bool operator()(I first, S last, Pred pred, Proj proj = {}) const
{
return ranges::find_if(first, last, std::ref(pred), std::ref(proj)) != last;
}
template<ranges::input_range R, class Proj = std::identity,
std::indirect_unary_predicate
<std::projected<ranges::iterator_t<R>, Proj>> Pred>
constexpr bool operator()(R&& r, Pred pred, Proj proj = {}) const
{
return operator()(ranges::begin(r), ranges::end(r),
std::ref(pred), std::ref(proj));
}
template<ranges::forward_range R, class Proj = std::identity,
std::indirect_unary_predicate
<std::projected<ranges::iterator_t<R>, Proj>> Pred>
constexpr bool operator()(R&& r, Pred pred, Proj proj = {}) const
{
return operator()(ranges::begin(r),
ranges::next(ranges::begin(r), ranges::end(r)),
std::ref(pred), std::ref(proj));
}
};
inline constexpr any_of_fn any_of;
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| none_of (5,6) |
struct none_of_fn
{
template<std::input_iterator I, std::sentinel_for<I> S, class Proj = std::identity,
std::indirect_unary_predicate<std::projected<I, Proj>> Pred>
constexpr bool operator()(I first, S last, Pred pred, Proj proj = {}) const
{
return ranges::find_if(first, last, std::ref(pred), std::ref(proj)) == last;
}
template<ranges::input_range R, class Proj = std::identity,
std::indirect_unary_predicate
<std::projected<ranges::iterator_t<R>, Proj>> Pred>
constexpr bool operator()(R&& r, Pred pred, Proj proj = {}) const
{
return operator()(ranges::begin(r), ranges::end(r),
std::ref(pred), std::ref(proj));
}
template<ranges::forward_range R, class Proj = std::identity,
std::indirect_unary_predicate
<std::projected<ranges::iterator_t<R>, Proj>> Pred>
constexpr bool operator()(R&& r, Pred pred, Proj proj = {}) const
{
return operator()(ranges::begin(r),
ranges::next(ranges::begin(r), ranges::end(r)),
std::ref(pred), std::ref(proj));
}
};
inline constexpr none_of_fn none_of;
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示例
运行此代码
#include <algorithm> #include <functional> #include <iostream> #include <iterator> #include <numeric> #include <vector> namespace ranges = std::ranges; constexpr bool some_of(auto&& r, auto&& pred) // 部分而非全部 { return not (ranges::all_of(r, pred) or ranges::none_of(r, pred)); } constexpr auto w = {1, 2, 3}; static_assert(!some_of(w, [](int x) { return x < 1; })); static_assert( some_of(w, [](int x) { return x < 2; })); static_assert(!some_of(w, [](int x) { return x < 4; })); int main() { std::vector<int> v(10, 2); std::partial_sum(v.cbegin(), v.cend(), v.begin()); std::cout << "数列中的数字："; ranges::copy(v, std::ostream_iterator<int>(std::cout, " ")); std::cout << '\n'; if (ranges::all_of(v.cbegin(), v.cend(), [](int i) { return i % 2 == 0; })) std::cout << "所有数字均为偶数\n"; if (ranges::none_of(v, std::bind(std::modulus<int>(), std::placeholders::_1, 2))) std::cout << "没有数字是奇数\n"; auto DivisibleBy = [](int d) { return [d](int m) { return m % d == 0; }; }; if (ranges::any_of(v, DivisibleBy(7))) std::cout << "至少有一个数字能被7整除\n"; }
输出：
数列中的数字：2 4 6 8 10 12 14 16 18 20 所有数字均为偶数 没有数字是奇数 至少有一个数字能被7整除
参见
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(C++11)
(C++11)
(C++11)
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检查谓词是否对范围中的所有、任一或没有元素为
true
(函数模板) |