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1.. Algorithms/Transformation Algorithms//partition |85
2
3partition
4=========
5
6Synopsis
7--------
8
9.. parsed-literal::
10
11    template<
12          typename Seq
13        , typename Pred
14        , typename In1 = |unspecified|
15        , typename In2 = |unspecified|
16        >
17    struct partition
18    {
19        typedef |unspecified| type;
20    };
21
22
23Description
24-----------
25
26Returns a pair of sequences together containing all elements in the range
27|begin/end<Seq>| split into two groups based on the predicate ``Pred``.
28``partition`` is a synonym for |stable_partition|.
29
30|transformation algorithm disclaimer|
31
32
33Header
34------
35
36.. parsed-literal::
37
38    #include <boost/mpl/partition.hpp>
39
40
41Model of
42--------
43
44|Reversible Algorithm|
45
46
47Parameters
48----------
49
50+-------------------+-----------------------------------+-------------------------------+
51| Parameter         | Requirement                       | Description                   |
52+===================+===================================+===============================+
53| ``Seq``           | |Forward Sequence|                | An original sequence.         |
54+-------------------+-----------------------------------+-------------------------------+
55| ``Pred``          | Unary |Lambda Expression|         | A partitioning predicate.     |
56+-------------------+-----------------------------------+-------------------------------+
57| ``In1``, ``In2``  | |Inserter|                        | Output inserters.             |
58+-------------------+-----------------------------------+-------------------------------+
59
60
61Expression semantics
62--------------------
63
64|Semantics disclaimer...| |Reversible Algorithm|.
65
66For any |Forward Sequence| ``s``, an unary |Lambda Expression| ``pred``, and |Inserter|\ s
67``in1`` and ``in2``:
68
69
70.. parsed-literal::
71
72    typedef partition<s,pred,in1,in2>::type r;
73
74:Return type:
75    A |pair|.
76
77:Semantics:
78    Equivalent to
79
80    .. parsed-literal::
81
82        typedef stable_partition<s,pred,in1,in2>::type r;
83
84
85Complexity
86----------
87
88Linear. Exactly ``size<s>::value`` applications of ``pred``, and ``size<s>::value``
89of summarized ``in1::operation`` / ``in2::operation`` applications.
90
91
92Example
93-------
94
95.. parsed-literal::
96
97    template< typename N > struct is_odd : bool_<(N::value % 2)> {};
98
99    typedef partition<
100          range_c<int,0,10>
101        , is_odd<_1>
102        , back_inserter< vector<> >
103        , back_inserter< vector<> >
104        >::type r;
105
106    BOOST_MPL_ASSERT(( equal< r::first, vector_c<int,1,3,5,7,9> > ));
107    BOOST_MPL_ASSERT(( equal< r::second, vector_c<int,0,2,4,6,8> > ));
108
109
110See also
111--------
112
113|Transformation Algorithms|, |Reversible Algorithm|, |reverse_partition|, |stable_partition|, |sort|
114
115
116.. copyright:: Copyright �  2001-2009 Aleksey Gurtovoy and David Abrahams
117   Distributed under the Boost Software License, Version 1.0. (See accompanying
118   file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
119