ceph/src/boost/libs/mpl/doc/src/refmanual/remove_if.rst

   1 .. Algorithms/Transformation Algorithms//remove_if |70
   2
   3 remove_if
   4 =========
   5
   6 Synopsis
   7 --------
   8
   9 .. parsed-literal::
  10
  11     template<
  12           typename Sequence
  13         , typename Pred
  14         , typename In = |unspecified|
  15         >
  16     struct remove_if
  17     {
  18         typedef |unspecified| type;
  19     };
  20
  21
  22 Description
  23 -----------
  24
  25 Returns a new sequence that contains all the elements from |begin/end<Sequence>| range
  26 except those that satisfy the predicate ``Pred``.
  27
  28 .. Returns a copy of the original sequence with all elements satisfying the predicate
  29    ``Pred`` removed.
  30
  31 |transformation algorithm disclaimer|
  32
  33 Header
  34 ------
  35
  36 .. parsed-literal::
  37
  38     #include <boost/mpl/remove_if.hpp>
  39
  40
  41 Model of
  42 --------
  43
  44 |Reversible Algorithm|
  45
  46
  47 Parameters
  48 ----------
  49
  50 +---------------+-----------------------------------+-------------------------------+
  51 | Parameter     | Requirement                       | Description                   |
  52 +===============+===================================+===============================+
  53 | ``Sequence``  | |Forward Sequence|                | An original sequence.         |
  54 +---------------+-----------------------------------+-------------------------------+
  55 | ``Pred``      | Unary |Lambda Expression|         | A removal condition.          |
  56 +---------------+-----------------------------------+-------------------------------+
  57 | ``In``        | |Inserter|                        | An inserter.                  |
  58 +---------------+-----------------------------------+-------------------------------+
  59
  60
  61 Expression semantics
  62 --------------------
  63
  64 |Semantics disclaimer...| |Reversible Algorithm|.
  65
  66 For any |Forward Sequence| ``s``, and an |Inserter| ``in``, and an unary
  67 |Lambda Expression| ``pred``:
  68
  69
  70 .. parsed-literal::
  71
  72     typedef remove_if<s,pred,in>::type r;
  73
  74 :Return type:
  75     A type.
  76
  77 :Semantics:
  78     Equivalent to
  79
  80     .. parsed-literal::
  81
  82         typedef lambda<pred>::type p;
  83         typedef lambda<in::operation>::type op;
  84
  85         typedef fold<
  86               s
  87             , in::state
  88             , eval_if<
  89                   apply_wrap\ ``1``\<p,_2>
  90                 , identity<_1>
  91                 , apply_wrap\ ``2``\<op,_1,_2>
  92                 >
  93             >::type r;
  94
  95
  96 Complexity
  97 ----------
  98
  99 Linear. Performs exactly ``size<s>::value`` applications of ``pred``, and at
 100 most ``size<s>::value`` insertions.
 101
 102
 103 Example
 104 -------
 105
 106 .. parsed-literal::
 107
 108     typedef vector_c<int,1,4,5,2,7,5,3,5>::type numbers;
 109     typedef remove_if< numbers, greater<_,int_<4> > >::type result;
 110
 111     BOOST_MPL_ASSERT(( equal< result,vector_c<int,1,4,2,3>,equal_to<_,_> > ));
 112
 113
 114 See also
 115 --------
 116
 117 |Transformation Algorithms|, |Reversible Algorithm|, |reverse_remove_if|, |remove|, |copy_if|, |replace_if|
 118
 119
 120 .. copyright:: Copyright ©  2001-2009 Aleksey Gurtovoy and David Abrahams
 121    Distributed under the Boost Software License, Version 1.0. (See accompanying
 122    file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)