Re: [Boost-users] Searching through a vector of tuples...

From: Graham Reitz (graham.cpp_at_[hidden])
Date: 2007-08-14 23:45:26

Thanks Folks!  I really appreciate the help!  That's just what I needed.

Graham

On 8/13/07, Richard Dingwall <rdingwall_at_[hidden]> wrote:
> The following appears to work (it compiles :)):
>
> #include <boost/tuple/tuple.hpp>
> #include <boost/bind.hpp>
> #include <vector>
> #include <algorithm>
> #include <cassert>
>
> template<int N, class tuple_type> inline
> typename boost::tuples::element<N, tuple_type>::type & get(tuple_type & t)
> {
>     return boost::tuples::get<N>(t);
> }
>
> int main(const int argc, const char ** argv)
> {
>
>     typedef boost::tuples::tuple<int, double> some_tuple;
>
>     std::vector<some_tuple> vec_of_some_tuples;
>
>     std::vector<some_tuple>::iterator
> result(std::find_if(vec_of_some_tuples.begin(),
> vec_of_some_tuples.end(), boost::bind(get<0, some_tuple>, ::_1) == 42));
>
>     assert(result != vec_of_some_tuples.end());
>
>     return 0;
> }
>
> Where 42 is the item you're looking for. See this post for original get():
> http://lists.boost.org/boost-users/2007/01/24529.php
>
> Otherwise, use a map?
>
> Richard
>
>
> On 8/14/07, David Abrahams <dave_at_[hidden] > wrote:
> >
> > on Mon Aug 13 2007, "Graham Reitz" <graham.cpp-AT-gmail.com> wrote:
> >
> > > typedef boost::tuples::tuple<int,double> some_tuple;
> > >
> > > std::vector<some_tuple> vec_of_some_tuples;
> > >
> > > // ... stuff some data into the vector
> > >
> > > // ... search for a specific int in the vector of some_tuple
> > >
> > > What would be a good method, using an stl algorithm, to search through
> > > the vector above to match only the int portion of the tuple (ignoring
> > > the double)?
> >
> > Use std::find with a boost::transform_iterator over a function
> > returning the first member of the tuple, then extract the resulting
> > iterator's base() iterator.
> >
> > HTH,
> >
> > --
> > Dave Abrahams
> > Boost Consulting
> > http://www.boost-consulting.com
> >
> > The Astoria Seminar ==> http://www.astoriaseminar.com
> >
> > _______________________________________________
> > Boost-users mailing list
> > Boost-users_at_[hidden]
> > http://lists.boost.org/mailman/listinfo.cgi/boost-users
> >
>
>
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