Re: [Boost-users] [bimap] Creating a bimap fom a std::map

27 Nov 2009

      Lex Wassenberg wrote:
...
I am not sure wether I understand this whole discussion, but I think
that I do so I would like Edward to consider this:
Suppose you have a std::map<int, int> m with the elements (1,10),
(2,20), (3,20), (4,20), (5,30), and you code:
  Boost::bimap<int,int> bm(m);
Now what??
Bimap automatically adds the map data to the left side of the bimap. If 
any data can not be added, such as the (3,20), (4,20), it acts in 
exactly the same fashion as it normally would when one tries to insert a 
data pair which is not distinct both ways.

My point is that I wanted a constructor as above:

Boost::bimap<int,int> bm(m);

to do essentially:

bm.left.insert(m.begin(),m.end());

Evidently the implementor of bimap does not agree so I have chosen not 
to pursue this suggestion any further. But I doubt I will be the last 
person suggesting this.
...
Regards
Lex
...
-----Oorspronkelijk bericht-----
Van: boost-users-bounces@lists.boost.org [mailto:boost-users-
bounces@lists.boost.org] Namens Matias Capeletto
Verzonden: Wednesday, 25 November 2009 23:50
Aan: boost-users@lists.boost.org
Onderwerp: Re: [Boost-users] [bimap] Creating a bimap fom a std::map
...
Whether I go:
bm.left.insert( m.begin(), m.end() );
or
bm.right.insert( m.begin(), m.end() );
,when both types are the same, is totally irrelevant to further use
of
On Wed, Nov 25, 2009 at 5:35 PM, Edward Diener
<eldiener@tropicsoft.com>
wrote:
the
...
bimap. Is this not correct ?
No, it is not correct. A bimap is a mapping between two sets of
elements (named the left set, and the right set) that can be viewed as
a std map<L,R> or as a std map<R, L>. In this particular example both
sets hold elements of the same type but which one is the left and
which one is the right matters. Imagine that you need a mapping
between names and surnames
(bimap<tagged<string,name>,tagged<string,surname> >), and you want to
insert from a std::map<string,string> that maps from surnames to
names.
I hope it is more clear now.
Regards
Matias

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