...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
Front Page / Algorithms / Transformation Algorithms / partition |
template< typename Seq , typename Pred , typename In1 = unspecified , typename In2 = unspecified > struct partition { typedef unspecified type; };
Returns a pair of sequences together containing all elements in the range [begin<Seq>::type, end<Seq>::type) split into two groups based on the predicate Pred. partition is a synonym for stable_partition.
[Note: This wording applies to a no-inserter version(s) of the algorithm. See the Expression semantics subsection for a precise specification of the algorithm's details in all cases — end note]
#include <boost/mpl/partition.hpp>
Parameter | Requirement | Description |
---|---|---|
Seq | Forward Sequence | An original sequence. |
Pred | Unary Lambda Expression | A partitioning predicate. |
In1, In2 | Inserter | Output inserters. |
The semantics of an expression are defined only where they differ from, or are not defined in Reversible Algorithm.
For any Forward Sequence s, an unary Lambda Expression pred, and Inserters in1 and in2:
typedef partition<s,pred,in1,in2>::type r;
Return type: | A pair. |
---|---|
Semantics: | Equivalent to typedef stable_partition<s,pred,in1,in2>::type r; |
Linear. Exactly size<s>::value applications of pred, and size<s>::value of summarized in1::operation / in2::operation applications.
template< typename N > struct is_odd : bool_<(N::value % 2)> {}; typedef partition< range_c<int,0,10> , is_odd<_1> , back_inserter< vector<> > , back_inserter< vector<> > >::type r; BOOST_MPL_ASSERT(( equal< r::first, vector_c<int,1,3,5,7,9> > )); BOOST_MPL_ASSERT(( equal< r::second, vector_c<int,0,2,4,6,8> > ));