std::replace, std::replace_if - cppreference.com

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Definido no cabeçalho `<algorithm>`

`template< class ForwardIt, class T > void replace( ForwardIt first, ForwardIt last, const T& old_value, const T& new_value );`	(1)

`template< class ForwardIt, class UnaryPredicate, class T > void replace_if( ForwardIt first, ForwardIt last, UnaryPredicate p, const T& new_value );`	(2)

Substitui todos os elementos que satisfaçam os critérios específicos com new_value no [first, last) alcance. A primeira versão substitui os elementos que são iguais a old_value, a segunda versão substitui elementos para os quais predicado p retornos true.

Original:

Replaces all elements satisfying specific criteria with new_value in the range [first, last). The first version replaces the elements that are equal to old_value, the second version replaces elements for which predicate p returns true.

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Parâmetros

first, last	-	a gama de elementos ao processo Original: the range of elements to process The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
old_value	-	o valor de elementos a substituir Original: the value of elements to replace The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
p	-	unary predicate which returns `true` se o valor do elemento deve ser substituído Original: if the element value should be replaced The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. . The signature of the predicate function should be equivalent to the following: `bool pred(const Type &a);` The signature does not need to have `const &`, but the function must not modify the objects passed to it. The type `Type` must be such that an object of type `ForwardIt` can be dereferenced and then implicitly converted to `Type`.
new_value	-	o valor a ser usado como substituto Original: the value to use as replacement The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
Type requirements
-`ForwardIt` must meet the requirements of `ForwardIterator`.

Valor de retorno

(Nenhum)

Original:

(none)

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Complexidade

Exatamente last - first aplicações do predicado.

Original:

Exactly last - first applications of the predicate.

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Possível implementação

First version
template<class ForwardIt, class T> void replace(ForwardIt first, ForwardIt last, const T& old_value, const T& new_value) { for (; first != last; ++first) { if (first == old_value) { first = new_value; } } }
Second version
template<class ForwardIt, class UnaryPredicate, class T> void replace_if(ForwardIt first, ForwardIt last, UnaryPredicate p, const T& new_value) { for (; first != last; ++first) { if(p(first)) { first = new_value; } } }

First version

template<class ForwardIt, class T>
void replace(ForwardIt first, ForwardIt last,
             const T& old_value, const T& new_value)
{
    for (; first != last; ++first) {
        if (*first == old_value) {
            *first = new_value;
        }
    }
}

Second version

template<class ForwardIt, class UnaryPredicate, class T>
void replace_if(ForwardIt first, ForwardIt last,
                UnaryPredicate p, const T& new_value)
{
    for (; first != last; ++first) {
        if(p(*first)) {
            *first = new_value;
        }
    }
}

Exemplo

O código a seguir no primeiro substitui todas as ocorrências de 8 com 88 em um vetor de números inteiros. Em seguida, ele substitui todos os valores inferiores 5 com 55 .

Original:

The following code at first replaces all occurrences of 8 with 88 in a vector of integers. Then it replaces all values less than 5 with 55.

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#include <algorithm>
#include <array>
#include <iostream>
#include <functional>

int main()
{
    std::array<int, 10> s{5, 7, 4, 2, 8, 6, 1, 9, 0, 3};

    std::replace(s.begin(), s.end(), 8, 88);

    for (int a : s) {
        std::cout << a << " ";
    }
    std::cout << '\n';

    std::replace_if(s.begin(), s.end(), 
                    std::bind(std::less<int>(), std::placeholders::_1, 5), 55);
    for (int a : s) {
        std::cout << a << " ";
    }
    std::cout << '\n';
}

Saída:

5 7 4 2 88 6 1 9 0 3
5 7 55 55 99 6 55 9 55 55

Veja também


	copia um intervalo, substituindo elementos que satisfazem critérios específicos com outro valor Original: copies a range, replacing elements satisfying specific criteria with another value The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (modelo de função) [edit]