iterator adapter to iterate just the values in a map?

Question

I'm just getting back into C++ after a couple of years of doing a lot of C#, and recently Objective C.

One thing I've done before is to roll my own iterator adapter for std::map that will deref to just the value part, rather than the key-value pair. This is quite a common and natural thing to do. C# provides this facility with its Keys and Values properties of its Dictionary class. Objective-C's NSDictionary, similarly, has allKeys and allValues.

Since I've been "away", Boost has acquired the Range and ForEach libraries, which I am now using extensively. I wondered if between the two there was some facility to do the same, but I haven't been able to find anything.

I'm thinking of knocking something up using Boost's iterator adapters, but before I go down that route I thought I'd ask here if anyone knows of such a facility in Boost, or somewhere else ready made?

Answer 1

Replacing the previous answer, in case anybody else finds this like I did. As of boost 1.43, there are some commonly used range adaptors provided. In this case, you want boost::adaptors::map_values. The relevant example: http://www.boost.org/doc/libs/1_46_0/libs/range/doc/html/range/reference/adaptors/reference/map_values.html#range.reference.adaptors.reference.map_values.map_values_example