std::ranges:: replace_copy, std::ranges:: replace_copy_if, std::ranges:: replace_copy_result, std::ranges:: replace_copy_if_result

From cppreference.net

헤더 파일에 정의됨 `<algorithm>`
호출 시그니처
	(1)
template < std:: input_iterator I, std:: sentinel_for < I > S, class T1, class T2, std:: output_iterator < const T2 & > O, class Proj = std:: identity > requires std:: indirectly_copyable < I, O > && std:: indirect_binary_predicate < ranges:: equal_to , std :: projected < I, Proj > , const T1 * > constexpr replace_copy_result < I, O > replace_copy ( I first, S last, O result, const T1 & old_value, const T2 & new_value, Proj proj = { } ) ;			(C++20부터) (C++26까지)
template < std:: input_iterator I, std:: sentinel_for < I > S, class O, class Proj = std:: identity , class T1 = std :: projected_value_t < I, Proj > , class T2 = std:: iter_value_t < O > > requires std:: indirectly_copyable < I, O > && std:: indirect_binary_predicate < ranges:: equal_to , std :: projected < I, Proj > , const T1 * > && std:: output_iterator < O, const T2 & > constexpr replace_copy_result < I, O > replace_copy ( I first, S last, O result, const T1 & old_value, const T2 & new_value, Proj proj = { } ) ;			(C++26부터)
		(2)
template < ranges:: input_range R, class T1, class T2, std:: output_iterator < const T2 & > O, class Proj = std:: identity > requires std:: indirectly_copyable < ranges:: iterator_t < R > , O > && std:: indirect_binary_predicate < ranges:: equal_to , std :: projected < ranges:: iterator_t < R > , Proj > , const T1 * > constexpr replace_copy_result < ranges:: borrowed_iterator_t < R > , O > replace_copy ( R && r, O result, const T1 & old_value, const T2 & new_value, Proj proj = { } ) ;				(C++20부터) (C++26까지)
template < ranges:: input_range R, class O, class Proj = std:: identity , class T1 = std :: projected_value_t < ranges:: iterator_t < R > , Proj > , class T2 = std:: iter_value_t < O > > requires std:: indirectly_copyable < ranges:: iterator_t < R > , O > && std:: indirect_binary_predicate < ranges:: equal_to , std :: projected < ranges:: iterator_t < R > , Proj > , const T1 * > && std:: output_iterator < O, const T2 & > constexpr replace_copy_result < ranges:: borrowed_iterator_t < R > , O > replace_copy ( R && r, O result, const T1 & old_value, const T2 & new_value, Proj proj = { } ) ;				(C++26부터)
			(3)
template < std:: input_iterator I, std:: sentinel_for < I > S, class T, std:: output_iterator < const T & > O, class Proj = std:: identity , std:: indirect_unary_predicate < std :: projected < I, Proj >> Pred > requires std:: indirectly_copyable < I, O > constexpr replace_copy_if_result < I, O > replace_copy_if ( I first, S last, O result, Pred pred, const T & new_value, Proj proj = { } ) ;					(C++20부터) (C++26까지)
template < std:: input_iterator I, std:: sentinel_for < I > S, class O, class T = std:: iter_value_t < O > class Proj = std:: identity , std:: indirect_unary_predicate < std :: projected < I, Proj >> Pred > requires std:: indirectly_copyable < I, O > && std:: output_iterator < O, const T & > constexpr replace_copy_if_result < I, O > replace_copy_if ( I first, S last, O result, Pred pred, const T & new_value, Proj proj = { } ) ;					(C++26부터)
				(4)
template < ranges:: input_range R, class T, std:: output_iterator < const T & > O, class Proj = std:: identity , std:: indirect_unary_predicate < std :: projected < ranges:: iterator_t < R > , Proj >> Pred > requires std:: indirectly_copyable < ranges:: iterator_t < R > , O > constexpr replace_copy_if_result < ranges:: borrowed_iterator_t < R > , O > replace_copy_if ( R && r, O result, Pred pred, const T & new_value, Proj proj = { } ) ;						(C++20부터) (C++26까지)
template < ranges:: input_range R, class O, class T = std:: iter_value_t < O > class Proj = std:: identity , std:: indirect_unary_predicate < std :: projected < ranges:: iterator_t < R > , Proj >> Pred > requires std:: indirectly_copyable < ranges:: iterator_t < R > , O > && std:: output_iterator < O, const T & > constexpr replace_copy_if_result < ranges:: borrowed_iterator_t < R > , O > replace_copy_if ( R && r, O result, Pred pred, const T & new_value, Proj proj = { } ) ;						(C++26부터)
헬퍼 타입
template < class I, class O > using replace_copy_result = ranges:: in_out_result < I, O > ;					(5)	(C++20 이후)
template < class I, class O > using replace_copy_if_result = ranges:: in_out_result < I, O > ;					(6)	(C++20 이후)

소스 범위 [ first , last ) 의 요소들을 result 에서 시작하는 대상 범위로 복사하며, 특정 조건을 만족하는 모든 요소를 new_value 로 대체합니다. 소스와 대상 범위가 겹치는 경우 동작은 정의되지 않습니다.

1) old_value 와 동일한 모든 요소를 대체하며, 비교를 위해 std:: invoke ( proj, * ( first + ( i - result ) ) ) == old_value 를 사용합니다.

3) 술어 pred 가 true 로 평가되는 모든 요소를 대체합니다. 이때 평가 표현식은 std:: invoke ( pred, std:: invoke ( proj, * ( first + ( i - result ) ) ) ) 입니다.

2,4) (1,3) 와 동일하지만, r 를 소스 범위로 사용하며, 마치 ranges:: begin ( r ) 를 first 로, 그리고 ranges:: end ( r ) 를 last 로 사용하는 것과 같습니다.

이 페이지에서 설명하는 함수형 개체들은 algorithm function objects (일반적으로 niebloids 로 알려진)입니다. 즉:

명시적 템플릿 인수 목록은 이들 중 어느 것을 호출할 때도 지정할 수 없습니다.
이들 중 어느 것도 인수 의존 이름 검색 에 보이지 않습니다.
이들 중 어느 것이 함수 호출 연산자의 왼쪽 이름으로 일반 비한정 이름 검색 에 의해 발견될 때, 인수 의존 이름 검색 이 억제됩니다.

first, last	-	복사할 요소들의 범위 를 정의하는 반복자-감시자 쌍
r	-	복사할 요소들의 범위
result	-	대상 범위의 시작점
old_value	-	대체할 요소의 값
new_value	-	대체 값으로 사용할 값
pred	-	투영된 요소들에 적용할 predicate
proj	-	요소들에 적용할 projection

반환값

{ last, result + N } , 여기서

1,3) N = ranges:: distance ( first, last ) ;

2,4) N = ranges:: distance ( r ) .

복잡도

정확히 N 번의 해당 predicate comp 와 임의의 projection proj 의 적용.

가능한 구현

replace_copy (1,2)

struct replace_copy_fn
{
    template<std::input_iterator I, std::sentinel_for<I> S,
             class O, class Proj = std::identity,
             class T1 = std::projected_value_t<I, Proj>,
             class T2 = std::iter_value_t<O>>
    requires std::indirectly_copyable<I, O> &&
             std::indirect_binary_predicate
                 <ranges::equal_to, std::projected<I, Proj>, const T1*> &&
             std::output_iterator<O, const T2&>
    constexpr ranges::replace_copy_result<I, O>
        operator()(I first, S last, O result, const T1& old_value,
                   const T2& new_value, Proj proj = {}) const
    {
        for (; first != last; ++first, ++result)
            *result = (std::invoke(proj, *first) == old_value) ? new_value : *first;
        return {std::move(first), std::move(result)};
    }
    template<ranges::input_range R, class O, class Proj = std::identity,
             class T1 = std::projected_value_t<ranges::iterator_t<R>, Proj>,
             class T2 = std::iter_value_t<O>>
    requires std::indirectly_copyable<ranges::iterator_t<R>, O> &&
             std::indirect_binary_predicate
                 <ranges::equal_to,
                  std::projected<ranges::iterator_t<R>, Proj>, const T1*>
    constexpr ranges::replace_copy_result<ranges::borrowed_iterator_t<R>, O>
        operator()(R&& r, O result, const T1& old_value,
                   const T2& new_value, Proj proj = {}) const
    {
        return (*this)(ranges::begin(r), ranges::end(r), std::move(result),
                       old_value, new_value, std::move(proj));
    }
};
inline constexpr replace_copy_fn replace_copy {};

replace_copy_if (3,4)

struct replace_copy_if_fn
{
    template<std::input_iterator I, std::sentinel_for<I> S,
             class O, class T = std::iter_value_t<O>
             class Proj = std::identity,
             std::indirect_unary_predicate<std::projected<I, Proj>> Pred>
    requires std::indirectly_copyable<I, O> && std::output_iterator<O, const T&>
    constexpr ranges::replace_copy_if_result<I, O>
        operator()(I first, S last, O result, Pred pred,
                   const T& new_value, Proj proj = {}) const
    {
        for (; first != last; ++first, ++result)
             *result = std::invoke(pred, std::invoke(proj, *first)) ? new_value : *first;
        return {std::move(first), std::move(result)};
    }
    template<ranges::input_range R, class O, class T = std::iter_value_t<O>
             class Proj = std::identity,
             std::indirect_unary_predicate
                 <std::projected<ranges::iterator_t<R>, Proj>> Pred>
    requires std::indirectly_copyable<ranges::iterator_t<R>, O> &&
             std::output_iterator<O, const T&>
    constexpr ranges::replace_copy_if_result<ranges::borrowed_iterator_t<R>, O>
        operator()(R&& r, O result, Pred pred,
                   const T& new_value, Proj proj = {}) const
    {
        return (*this)(ranges::begin(r), ranges::end(r), std::move(result),
                       std::move(pred), new_value, std::move(proj));
    }
};
inline constexpr replace_copy_if_fn replace_copy_if {};

참고 사항

기능 테스트 매크로	값	표준	기능
`__cpp_lib_algorithm_default_value_type`	`202403`	(C++26)	목록 초기화 for algorithms ( 1-4 )

예제

이 코드 실행

#include <algorithm>
#include <array>
#include <complex>
#include <iostream>
#include <vector>
void println(const auto rem, const auto& v)
{
    for (std::cout << rem << ": "; const auto& e : v)
        std::cout << e << ' ';
    std::cout << '\n';
}
int main()
{    
    std::vector<int> o;
    std::array p{1, 6, 1, 6, 1, 6};
    o.resize(p.size());
    println("p", p);
    std::ranges::replace_copy(p, o.begin(), 6, 9);
    println("o", o);
    std::array q{1, 2, 3, 6, 7, 8, 4, 5};
    o.resize(q.size());
    println("q", q);
    std::ranges::replace_copy_if(q, o.begin(), [](int x) { return 5 < x; }, 5);
    println("o", o);
    std::vector<std::complex<short>> r{{1, 3}, {2, 2}, {4, 8}};
    std::vector<std::complex<float>> s(r.size());
    println("r", r);
    #ifdef __cpp_lib_algorithm_default_value_type
        std::ranges::replace_copy(r, s.begin(),
                                  {1, 3}, // T1이 추론됨
                                  {2.2, 4.8}); // T2가 추론됨
    #else
        std::ranges::replace_copy(r, s.begin(),
                                  std::complex<short>{1, 3},
                                  std::complex<float>{2.2, 4.8});
    #endif
    println("s", s);
    std::vector<std::complex<double>> b{{1, 3}, {2, 2}, {4, 8}},
                                      d(b.size());
    println("b", b);
    #ifdef __cpp_lib_algorithm_default_value_type
        std::ranges::replace_copy_if(b, d.begin(),
            [](std::complex<double> z){ return std::abs(z) < 5; },
            {4, 2}); // 가능합니다, T가 추론되기 때문입니다.
    #else
        std::ranges::replace_copy_if(b, d.begin(),
            [](std::complex<double> z){ return std::abs(z) < 5; },
            std::complex<double>{4, 2});
    #endif
    println("d", d);
}

출력:

p: 1 6 1 6 1 6
o: 1 9 1 9 1 9
q: 1 2 3 6 7 8 4 5
o: 1 2 3 5 5 5 4 5
r: (1,3) (2,2) (4,8)
s: (2.2,4.8) (2,2) (4,8)
b: (1,3) (2,2) (4,8)
d: (4,2) (4,2) (4,8)

참고 항목

ranges::replace ranges::replace_if (C++20) (C++20)	특정 조건을 만족하는 모든 값을 다른 값으로 대체함 (알고리즘 함수 객체)
replace_copy replace_copy_if	범위를 복사하면서 특정 조건을 만족하는 요소를 다른 값으로 대체함 (함수 템플릿)

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cppreference.net

Namespaces

Variants

std::ranges:: replace_copy, std::ranges:: replace_copy_if, std::ranges:: replace_copy_result, std::ranges:: replace_copy_if_result

목차

매개변수

반환값

복잡도

가능한 구현

참고 사항

예제

참고 항목