std::ranges:: replace, std::ranges:: replace_if

From cppreference.net

헤더에 정의됨 `<algorithm>`
호출 시그니처
	(1)
template < std:: input_iterator I, std:: sentinel_for < I > S, class T1, class T2, class Proj = std:: identity > requires std:: indirectly_writable < I, const T2 & > && std:: indirect_binary_predicate < ranges:: equal_to , std :: projected < I, Proj > , const T1 * > constexpr I replace ( I first, S last, 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 Proj = std:: identity , class T1 = std :: projected_value_t < I, Proj > , class T2 = T1 > requires std:: indirectly_writable < I, const T2 & > && std:: indirect_binary_predicate < ranges:: equal_to , std :: projected < I, Proj > , const T1 * > constexpr I replace ( I first, S last, const T1 & old_value, const T2 & new_value, Proj proj = { } ) ;			(C++26부터)
		(2)
template < ranges:: input_range R, class T1, class T2, class Proj = std:: identity > requires std:: indirectly_writable < ranges:: iterator_t < R > , const T2 & > && std:: indirect_binary_predicate < ranges:: equal_to , std :: projected < ranges:: iterator_t < R > , Proj > , const T1 * > constexpr ranges:: borrowed_iterator_t < R > replace ( R && r, const T1 & old_value, const T2 & new_value, Proj proj = { } ) ;				(C++20부터) (C++26까지)
template < ranges:: input_range R, class Proj = std:: identity , class T1 = std :: projected_value_t < ranges:: iterator_t < R > , Proj > , class T2 = T1 > requires std:: indirectly_writable < ranges:: iterator_t < R > , const T2 & > && std:: indirect_binary_predicate < ranges:: equal_to , std :: projected < ranges:: iterator_t < R > , Proj > , const T1 * > constexpr ranges:: borrowed_iterator_t < R > replace ( R && r, 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, class Proj = std:: identity , std:: indirect_unary_predicate < std :: projected < I, Proj >> Pred > requires std:: indirectly_writable < I, const T & > constexpr I replace_if ( I first, S last, Pred pred, const T & new_value, Proj proj = { } ) ;					(C++20부터) (C++26까지)
template < std:: input_iterator I, std:: sentinel_for < I > S, class Proj = std:: identity , class T = std :: projected_value_t < I, Proj > , std:: indirect_unary_predicate < std :: projected < I, Proj >> Pred > requires std:: indirectly_writable < I, const T & > constexpr I replace_if ( I first, S last, Pred pred, const T & new_value, Proj proj = { } ) ;					(C++26부터)
				(4)
template < ranges:: input_range R, class T, class Proj = std:: identity , std:: indirect_unary_predicate < std :: projected < ranges:: iterator_t < R > , Proj >> Pred > requires std:: indirectly_writable < ranges:: iterator_t < R > , const T & > constexpr ranges:: borrowed_iterator_t < R > replace_if ( R && r, Pred pred, const T & new_value, Proj proj = { } ) ;						(C++20부터) (C++26 이전까지)
template < ranges:: input_range R, class Proj = std:: identity , class T = std :: projected_value_t < ranges:: iterator_t < R > , Proj > , std:: indirect_unary_predicate < std :: projected < ranges:: iterator_t < R > , Proj >> Pred > requires std:: indirectly_writable < ranges:: iterator_t < R > , const T & > constexpr ranges:: borrowed_iterator_t < R > replace_if ( R && r, Pred pred, const T & new_value, Proj proj = { } ) ;						(C++26부터)

특정 조건을 만족하는 모든 요소를 범위 [ first , last ) 내에서 new_value 로 교체합니다.

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

3) 술어 pred 가 true 로 평가되는 모든 요소들을 대체합니다. 이때 평가 표현식은 std:: invoke ( pred, std:: invoke ( proj, * i ) ) 입니다.

2,4) (1,3) 와 동일하지만, r 를 범위로 사용하며, 마치 ranges:: begin ( r ) 를 first 로, 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 의존적查找 에 보이지 않습니다.
이들 중 어느 것이 함수 호출 연산자의 왼쪽 이름으로 일반 비한정查找 에 의해 발견될 때, 인수 의존적查找 가 억제됩니다.

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

replace_if (3,4)

struct replace_if_fn
{
    template<std::input_iterator I, std::sentinel_for<I> S,
             class Proj = std::identity, class T = std::projected_value_t<I, Proj>,
             std::indirect_unary_predicate<std::projected<I, Proj>> Pred>
    requires std::indirectly_writable<I, const T&>
    constexpr I operator()(I first, S last, Pred pred,
                           const T& new_value, Proj proj = {}) const
    {
        for (; first != last; ++first)
            if (!!std::invoke(pred, std::invoke(proj, *first)))
                *first = new_value;
        return std::move(first);
    }
    template<ranges::input_range R, class Proj = std::identity,
             class T = std::projected_value_t<ranges::iterator_t<R>, Proj>
             std::indirect_unary_predicate
                 <std::projected<ranges::iterator_t<R>, Proj>> Pred>
    requires std::indirectly_writable<ranges::iterator_t<R>, const T&>
    constexpr ranges::borrowed_iterator_t<R>
        operator()(R&& r, Pred pred, const T& new_value, Proj proj = {}) const
    {
        return (*this)(ranges::begin(r), ranges::end(r), std::move(pred),
                       new_value, std::move(proj));
    }
};
inline constexpr replace_if_fn replace_if{};

예제

이 코드 실행

#include <algorithm>
#include <array>
#include <complex>
#include <iostream>
void println(const auto& v)
{
    for (const auto& e : v)
        std::cout << e << ' ';
    std::cout << '\n';
}
int main()
{
    namespace ranges = std::ranges;
    std::array p{1, 6, 1, 6, 1, 6};
    println(p);
    ranges::replace(p, 6, 9);
    println(p);
    std::array q{1, 2, 3, 6, 7, 8, 4, 5};
    println(q);
    ranges::replace_if(q, [](int x) { return 5 < x; }, 5);
    println(q);
    std::array<std::complex<double>, 2> nums{{{1, 3}, {1, 3}}};
    println(nums);
    #ifdef __cpp_lib_algorithm_default_value_type
        ranges::replace(nums, {1, 3}, {4, 2});
    #else
        ranges::replace(nums, std::complex<double>{1, 3}, std::complex<double>{4, 2});
    #endif
    println(nums);
}

출력:

1 6 1 6 1 6
1 9 1 9 1 9
1 2 3 6 7 8 4 5
1 2 3 5 5 5 4 5
(1,3) (1,3)
(4,2) (4,2)

참고 항목

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

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first, last	-	처리할 요소들의 범위 를 정의하는 반복자-감시자 쌍
r	-	처리할 요소들의 범위
old_value	-	대체할 요소들의 값
new_value	-	대체 값으로 사용할 값
pred	-	투영된 요소들에 적용할 predicate
proj	-	요소들에 적용할 projection

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Namespaces

Variants

std::ranges:: replace, std::ranges:: replace_if

목차

매개변수

반환값

복잡도

참고 사항

가능한 구현

예제

참고 항목