Re: Passing other types to std::set::erase().

I have a class where each instance has a unique ID associated with it,
like this (I use "..." to mean "other things", not a variable
parameter list):

typedef ... ID;

class Data {
public:
   Data (ID id, ...);
   bool operator < (const Data &d) const throw () { return id_ <
d.id_; }
   ...
private:
   ID id_;
   ...
};

Instances are equivalent if their IDs are equivalent. I am storing
these in an std::set<Data>. I'd like to be able to erase elements from
the set given only an ID, that is:

std::set<Data> somedata = ...;
ID id = ...;
somedata.erase(id);

I've found two ways to make this work, neither are ideal for reasons I
don't want to get in to:

  1) Provide an implicit Data(ID) constructor to construct dummy Data
instances used for ID comparisons.

  2) Use an std::map<ID,Data> instead.

Is there a way I can erase elements from the set by ID without
constructing dummy Data instances, and without using some other
container type instead?