Synopsis

template<
      typename Seq
    , typename Pred
    , typename In1 = |unspecified|
    , typename In2 = |unspecified|
    >
struct partition
{
    typedef |unspecified| type;
};

Description

Returns a pair of sequences together containing all elements in the range |begin/end<Seq>| split into two groups based on the predicate Pred. partition is a synonym for |stable_partition|.

|transformation algorithm disclaimer|

Header

#include <boost/mpl/partition.hpp>

Model of

|Reversible Algorithm|

Parameters

Expression semantics

|Semantics disclaimer...| |Reversible Algorithm|.

For any |Forward Sequence| s, an unary |Lambda Expression| pred, and |Inserter|s in1 and in2:

typedef partition<s,pred,in1,in2>::type r;

typedef stable_partition<s,pred,in1,in2>::type r;

Complexity

Linear. Exactly size<s>::value applications of pred, and size<s>::value of summarized in1::operation / in2::operation applications.

Example

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> > ));

See also

|Transformation Algorithms|, |Reversible Algorithm|, |reverse_partition|, |stable_partition|, |sort|