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source: downloads/boost_1_34_1/libs/mpl/doc/src/refmanual/erase.rst @ 29

Last change on this file since 29 was 29, checked in by landauf, 17 years ago

updated boost from 1_33_1 to 1_34_1
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erase

Synopsis

template<
      typename Sequence
    , typename First
    , typename Last = |unspecified|
    >
struct erase
{
    typedef |unspecified| type;
};

Description

erase performs a removal of one or more adjacent elements in the sequence starting from an arbitrary position.

Parameters

Parameter Requirement Description
Sequence |Extensible Sequence| or |Extensible Associative Sequence| A sequence to erase from.
First |Forward Iterator| An iterator to the beginning of the range to be erased.
Last |Forward Iterator| An iterator past-the-end of the range to be erased.

Expression semantics

For any |Extensible Sequence| s, and iterators pos, first and last into s:

typedef erase<s,first,last>::type r;
Return type:

|Extensible Sequence|.
Precondition:

[first,last) is a valid range in s.
Semantics:

r is a new sequence, |concept-identical| to s, of the following elements: [begin<s>::type, pos), [last, end<s>::type).
Postcondition:

The relative order of the elements in r is the same as in s;

size<r>::value == size<s>::value - distance<first,last>::value

typedef erase<s,pos>::type r;
Return type:

|Extensible Sequence|.
Precondition:

pos is a dereferenceable iterator in s.
Semantics:

Equivalent to

typedef erase< s,pos,next<pos>::type >::type r;

For any |Extensible Associative Sequence| s, and iterator pos into s:

typedef erase<s,pos>::type r;
Return type:|Extensible Sequence|.
Precondition:pos is a dereferenceable iterator to s.
Semantics:Erases the element at a specific position pos; equivalent to erase_key<s, deref<pos>::type >::type.
Postcondition:size<r>::value == size<s>::value - 1.

Complexity

Sequence archetype Complexity (the range form)
|Extensible Associative Sequence| Amortized constant time.
|Extensible Sequence| Quadratic in the worst case, linear at best.

Example

typedef vector_c<int,1,0,5,1,7,5,0,5> values;
typedef find< values, integral_c<int,7> >::type pos;
typedef erase<values,pos>::type result;
BOOST_MPL_ASSERT_RELATION( size<result>::value, ==, 7 );
typedef find<result, integral_c<int,7> >::type iter;
BOOST_MPL_ASSERT(( is_same< iter, end<result>::type > ));

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