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

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Déclaré dans l'en-tête `<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)

Remplace tous les éléments répondant à des critères spécifiques new_value dans le [first, last) gamme. La première version remplace les éléments qui sont égaux à old_value, la deuxième version remplace les éléments pour lesquels prédicat retourne p 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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Paramètres

first, last	-	l'ensemble d'éléments de processus 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	-	la valeur des éléments à remplacer 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	-	prédicat unéaire qui retourne `true` si la valeur de l'élément doit être remplacé 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. . L'expression `p(v)` doit pouvoir être convertie à `bool` pour tout argument `v` de type (possiblement const) `VT`, où `VT` est le type de valeur de `ForwardIt`, inconditionellement de value category, et ne doit pas modifier `v`. Ainsi, un type-paramètre `VT&`n'est pas permis ainsi que pour `VT` sauf pour `VT` un déplacement est équivalent à une copie (depuis C++11).
new_value	-	la valeur à utiliser en remplacement 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`.

Retourne la valeur

(Aucun)

Original:

(none)

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Complexité

Exactement last - first applications du prédicat .

Original:

Exactly last - first applications of the predicate.

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Mise en œuvre possible

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;
        }
    }
}

Exemple

Le code suivant au début remplace toutes les occurrences de 8 avec 88 dans un vecteur d'entiers. Puis il remplace toutes les valeurs inférieures à 55 .. 5

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';
}

Résultat :

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

Voir aussi


	copie d'une plage, le remplacement des éléments satisfaisant à des critères spécifiques à une autre valeur 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. (fonction générique) [edit]