Re: [Boost-users] multi_index_comtainer questions

Vladimir Voronkov writes:

Hi again,

Thanks for the answers, they helped my. Now I have come with some another probably stupid questions.

I've changed the initial example by adding some attribute to the element. Let's say int.

[...]

typedef UsersContainer::nth_index<2>::type UsersSelected;

This flag has not many possible values and most probably there will be many pairs in the container with the same value of this flag. Now I want to enumerate all values in the container with some specific value of this flag. There are many ways to do that. 1. Use lower_bound for getting iterator for the UsersSelected index. 2. implement own iterator that use some int value as a parameter.

But the ideal solution would be to expose some kind of "view" of the container that behaves like list, so we could use it's iterator from begin() to end() taking only necessary elements.

Is that possible?

The closest you can get to that, I guess, is to use equal_range(n), which returns a pair of iterators defining the range of elements with second==n (similar as the "begin()" and "end()" iterators you're after.) HTH, Joaquín M López Muñoz Telefónica, Investigación y Desarrollo