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

<p>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.</p>

<p>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.</p>

<p>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?</p>

I don't think there's anything out of the box.  You can use boost::make_transform.
```
```
template<typename T1, typename T2> T2& take_second(const std::pair<T1, T2> &a_pair) 
{
  return a_pair.second;
}

void run_map_value()
{
  map<int,string> a_map;
  a_map[0] = "zero";
  a_map[1] = "one";
  a_map[2] = "two";
  copy( boost::make_transform_iterator(a_map.begin(), take_second<int, string>),
    boost::make_transform_iterator(a_map.end(), take_second<int, string>),
    ostream_iterator<string>(cout, "\n")
    );
}
```
```