std::partition

 

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Funktionen Original: Functions The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
Nicht-modifizierende Sequenz Operationen Original: Non-modifying sequence operations The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
all_of any_of none_of (C++11) (C++11) (C++11) for_each count count_if mismatch equal	find find_if find_if_not (C++11) find_end find_first_of adjacent_find search search_n
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copy copy_if (C++11) copy_n (C++11) copy_backward move (C++11) move_backward (C++11) fill fill_n transform generate generate_n remove remove_if remove_copy remove_copy_if	replace replace_if replace_copy replace_copy_if swap swap_ranges iter_swap reverse reverse_copy rotate rotate_copy random_shuffle shuffle   (C++11) unique unique_copy
Partitionierungsoperationen Original: Partitioning operations The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
is_partitioned (C++11) partition partition_copy (C++11)	stable_partition partition_point (C++11)
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is_sorted (C++11) is_sorted_until (C++11) sort	partial_sort partial_sort_copy stable_sort nth_element
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merge inplace_merge includes	set_difference set_intersection set_symmetric_difference set_union
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max max_element min min_element minmax (C++11) minmax_element (C++11)	lexicographical_compare is_permutation (C++11) next_permutation prev_permutation
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definiert in Header <algorithm>
template<class BidirIt, class UnaryPredicate > BidirectionalIterator partition( BidirIt first, BidirIt last,                                  UnaryPredicate p ); template<class ForwardIt, class UnaryPredicate > ForwardIt partition( ForwardIt first, ForwardIt last,                      UnaryPredicate p );		(bis C + +11) (seit C++11)

Ordnet die Elemente im Bereich [first, last) derart, daß alle Elemente für die das Prädikat p kehrt true vorausgehen, für die die Elemente Prädikats p kehrt false. Relative Reihenfolge der Elemente ist nicht erhalten .

Original:

Reorders the elements in the range [first, last) in such a way that all elements for which the predicate p returns true precede the elements for which predicate p returns false. Relative order of the elements is not preserved.

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Parameter

first, last	-	der Bereich von Elementen neu zu ordnen Original: the range of elements to reorder 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 wenn das Element sollte vor anderen Elementen bestellt werden Original: if the element should be ordered before other elements 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. ​
Type requirements
- BidirIt must meet the requirements of BidirectionalIterator.
- ForwardIt must meet the requirements of ValueSwappable and ForwardIterator. However, the operation is more efficient if ForwardIt also satisfies the requirements of BidirectionalIterator

Rückgabewert

Iterator auf das erste Element der zweiten Gruppe .

Original:

Iterator to the first element of the second group.

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Komplexität

Genau last-first Anwendungen des Prädikats und höchstens last-first Swaps. Wenn ForwardIt erfüllt die Anforderungen der BidirectionalIterator höchstens (last-first)/2 Swaps fertig sind .

Original:

Exactly last-first applications of the predicate and at most last-first swaps. If ForwardIt meets the requirements of BidirectionalIterator at most (last-first)/2 swaps are done.

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Mögliche Implementierung

template<class BidirIt, class UnaryPredicate> BidirIt partition(BidirIt first, BidirIt last, UnaryPredicate p){while(1){while((first != last)&& p(*first)){++first;}if(first == last--)break;while((first != last)&&!p(*last)){--last;}if(first == last)break;std::swap(*first++, *last);}return first;}

Beispiel

#include <algorithm>#include <functional>#include <iostream>#include <iterator>#include <vector>   bool is_even(int i){return i %2==0;}   int main(){std::vector<int> v;for(int i =0; i <10;++i) v.push_back(i);   std::cout<<"Original vector:\n ";std::copy(v.begin(), v.end(), std::ostream_iterator<int>(std::cout, " "));   // Partition the vectorstd::vector<int>::iterator p = std::partition(v.begin(), v.end(), std::ptr_fun(is_even));   std::cout<<"\nPartitioned vector:\n ";std::copy(v.begin(), v.end(), std::ostream_iterator<int>(std::cout, " "));std::cout<<"\nBefore partition:\n ";std::copy(v.begin(), p, std::ostream_iterator<int>(std::cout, " "));std::cout<<"\nAfter partition:\n ";std::copy(p, v.end(), std::ostream_iterator<int>(std::cout, " "));}

Possible output:

Original vector: 0 1 2 3 4 5 6 7 8 9 Partitioned vector: 0 8 2 6 4 5 3 7 1 9 Before partition: 0 8 2 6 4 After partition: 5 3 7 1 9

Siehe auch

is_partitioned (C++11)	bestimmt, ob der Bereich von der gegebenen Prädikat partitioniert ist Original: determines if the range is partitioned by the given predicate The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (Funktions-Template)
stable_partition	trennt Elemente in zwei Gruppen unter Beibehaltung ihrer relativen Ordnung Original: divides elements into two groups while preserving their relative order The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (Funktions-Template)