std::replace, std::replace_if

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C++
 
算法库
功能
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Functions
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修改序列操作
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Non-modifying sequence operations
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all_of
any_of
none_of		（C++11）
（C++11）
（C++11）
for_each
count
count_if
mismatch
equal
修改序列操作
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Modifying sequence operations
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分区操作
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Partitioning operations
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is_partitioned（C++11）
partition
partition_copy（C++11）
排序操作（排序的区间）
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Sorting operations (on sorted ranges)
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is_sorted（C++11）
is_sorted_until（C++11）
sort
二进制搜索操作（排序的区间）
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Binary search operations (on sorted ranges)
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设置操作（排序的区间）
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Set operations (on sorted ranges)
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堆的操作
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Heap operations
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最小/最大操作
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Minimum/maximum operations
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数字操作
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Numeric operations
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C库
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C library
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Defined in header <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)
替换new_value的范围内[first, last)满足特定条件的所有元素。第一个版本取代元素是等于old_value，第二个版本替换元素的谓词p回报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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目录

[编辑] 参数

first, last -
元素的范围内进行处理
Original:
the range of elements to process
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old_value -
的值的元素来代替
Original:
the value of elements to replace
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p - unary predicate which returns ​true
如果元素的值应进行更换
Original:
if the element value should be replaced
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.

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 -
要使用的值作为替代品
Original:
the value to use as replacement
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Type requirements
-
ForwardIt must meet the requirements of ForwardIterator.

[编辑] 返回值

（无）
Original:
(none)
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[编辑] 复杂性

究竟last - first的谓词中的应用.
Original:
Exactly last - first applications of the predicate.
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[编辑] 可能的实现

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;
        }
    }
}

[编辑] 为例

下面的代码在第一次替换所有出现的888的向量整数。然后，它会取代所有的值小于555 .
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';
}

Output: 

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

[编辑] 另请参阅
复制的范围内，更换满足特定条件的元素与另一个值
Original:
copies a range, replacing elements satisfying specific criteria with another value
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（函数模板） [edit]
来自“http://zh.cppreference.com/mwiki/index.php?title=cpp/algorithm/replace&oldid=27803”