114 lines
2.6 KiB
ReStructuredText
114 lines
2.6 KiB
ReStructuredText
.. Algorithms/Transformation Algorithms//partition |85
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partition
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=========
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Synopsis
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--------
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.. parsed-literal::
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template<
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typename Seq
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, typename Pred
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, typename In1 = |unspecified|
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, typename In2 = |unspecified|
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>
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struct partition
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{
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typedef |unspecified| type;
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};
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Description
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-----------
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Returns a pair of sequences together containing all elements in the range
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|begin/end<Seq>| split into two groups based on the predicate ``Pred``.
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``partition`` is a synonym for |stable_partition|.
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|transformation algorithm disclaimer|
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Header
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------
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.. parsed-literal::
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#include <boost/mpl/partition.hpp>
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Model of
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--------
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|Reversible Algorithm|
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Parameters
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----------
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+-------------------+-----------------------------------+-------------------------------+
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| Parameter | Requirement | Description |
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+===================+===================================+===============================+
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| ``Seq`` | |Forward Sequence| | An original sequence. |
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+-------------------+-----------------------------------+-------------------------------+
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| ``Pred`` | Unary |Lambda Expression| | A partitioning predicate. |
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+-------------------+-----------------------------------+-------------------------------+
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| ``In1``, ``In2`` | |Inserter| | Output inserters. |
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+-------------------+-----------------------------------+-------------------------------+
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Expression semantics
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--------------------
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|Semantics disclaimer...| |Reversible Algorithm|.
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For any |Forward Sequence| ``s``, an unary |Lambda Expression| ``pred``, and |Inserter|\ s
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``in1`` and ``in2``:
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.. parsed-literal::
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typedef partition<s,pred,in1,in2>::type r;
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:Return type:
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A |pair|.
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:Semantics:
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Equivalent to
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.. parsed-literal::
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typedef stable_partition<s,pred,in1,in2>::type r;
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Complexity
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----------
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Linear. Exactly ``size<s>::value`` applications of ``pred``, and ``size<s>::value``
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of summarized ``in1::operation`` / ``in2::operation`` applications.
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Example
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-------
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.. parsed-literal::
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template< typename N > struct is_odd : bool_<(N::value % 2)> {};
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typedef partition<
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range_c<int,0,10>
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, is_odd<_1>
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, back_inserter< vector<> >
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, back_inserter< vector<> >
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>::type r;
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BOOST_MPL_ASSERT(( equal< r::first, vector_c<int,1,3,5,7,9> > ));
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BOOST_MPL_ASSERT(( equal< r::second, vector_c<int,0,2,4,6,8> > ));
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See also
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--------
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|Transformation Algorithms|, |Reversible Algorithm|, |reverse_partition|, |stable_partition|, |sort|
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