std::remove_copy, std::remove_copy_if
Defined in header
<algorithm>
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template< class InputIt, class OutputIt, class T >
OutputIt remove_copy( InputIt first, InputIt last, OutputIt d_first, |
(1) | |
template< class ExecutionPolicy, class InputIt, class OutputIt, class T >
OutputIt remove_copy( ExecutionPolicy&& policy, InputIt first, InputIt last, OutputIt d_first, |
(2) | (since C++17) |
template< class InputIt, class OutputIt, class UnaryPredicate >
OutputIt remove_copy_if( InputIt first, InputIt last, OutputIt d_first, |
(3) | |
template< class ExecutionPolicy, class InputIt, class OutputIt, class UnaryPredicate >
OutputIt remove_copy_if( ExecutionPolicy&& policy, InputIt first, InputIt last, OutputIt d_first, |
(4) | (since C++17) |
Copies elements from the range [first, last)
, to another range beginning at d_first
, omitting the elements which satisfy specific criteria. Source and destination ranges cannot overlap.
value
.p
returns true.policy
. These overloads do not participate in overload resolution unless std::is_execution_policy_v<std::decay_t<ExecutionPolicy>> is true
Contents |
[edit] Parameters
first, last | - | the range of elements to copy |
d_first | - | the beginning of the destination range. |
value | - | the value of the elements not to copy |
policy | - | the execution policy to use. See execution policy for details. |
Type requirements | ||
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InputIt must meet the requirements of InputIterator .
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OutputIt must meet the requirements of OutputIterator .
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UnaryPredicate must meet the requirements of Predicate .
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[edit] Return value
Iterator to the element past the last element copied.
[edit] Complexity
Exactly last - first
applications of the predicate.
[edit] Exceptions
The overloads with a template parameter named ExecutionPolicy
report errors as follows:
- If execution of a function invoked as part of the algorithm throws an exception,
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- if
policy
is std::parallel_vector_execution_policy, std::terminate is called - if
policy
is std::sequential_execution_policy or std::parallel_execution_policy, the algorithm exits with an std::exception_list containing all uncaught exceptions. If there was only one uncaught exception, the algorithm may rethrow it without wrapping in std::exception_list. It is unspecified how much work the algorithm will perform before returning after the first exception was encountered. - if
policy
is some other type, the behavior is implementation-defined
- if
- If the algorithm fails to allocate memory (either for itself or to construct an std::exception_list when handling a user exception), std::bad_alloc is thrown.
[edit] Possible implementation
First version |
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template<class InputIt, class OutputIt, class T> OutputIt remove_copy(InputIt first, InputIt last, OutputIt d_first, const T& value) { for (; first != last; ++first) { if (!(*first == value)) { *d_first++ = *first; } } return d_first; } |
Second version |
template<class InputIt, class OutputIt, class UnaryPredicate> OutputIt remove_copy_if(InputIt first, InputIt last, OutputIt d_first, UnaryPredicate p) { for (; first != last; ++first) { if (!p(*first)) { *d_first++ = *first; } } return d_first; } |
[edit] Example
The following code outputs a string while erasing the spaces on the fly.
#include <algorithm> #include <iterator> #include <string> #include <iostream> int main() { std::string str = "Text with some spaces"; std::cout << "before: " << str << "\n"; std::cout << "after: "; std::remove_copy(str.begin(), str.end(), std::ostream_iterator<char>(std::cout), ' '); std::cout << '\n'; }
Output:
before: Text with some spaces after: Textwithsomespaces
[edit] See also
removes elements satisfying specific criteria (function template) |
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(C++11)
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copies a range of elements to a new location (function template) |
(parallelism TS)
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parallelized version of std::remove_copy (function template) |
(parallelism TS)
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parallelized version of std::remove_copy_if (function template) |