Still I'm having difficulties with understanding your question, but let me try my hand
Your are good! :) I should knock myself for not sending you a snippet code below you can fiind a "small" example with only 2 indices ******** BEGIN CODE ******** typedef int handle; typedef int group_id; struct NodeBase:boost::enable_shared_from_this<NodeBase> { virtual ~NodeBase(){} virtual group_id memberOf()const=0; virtual handle getHandle()const=0; }; struct NodeType:NodeBase { NodeType(handle h,group_id gid):h(h),gid(gid){} virtual group_id memberOf()const{return gid;} virtual handle getHandle()const{return h;} private: group_id gid; handle h; }; struct NodeBaseHandleExtractor { typedef handle result_type; result_type operator()(const boost::shared_ptr<NodeBase>& x) { return x->getHandle(); } }; struct NodeBaseGroupIdExtractor { typedef group_id result_type; result_type operator()(const boost::shared_ptr<NodeBase>& x) { return x->memberOf(); } }; typedef boost::multi_index::multi_index_container< boost::shared_ptr<NodeBase>, boost::multi_index::indexed_by< boost::multi_index::ordered_unique< NodeBaseHandleExtractor
, boost::multi_index::ordered_non_unique<
NodeBaseGroupIdExtractor
NodePtrSet;
int main() { NodePtrSet ns; typedef boost::shared_ptr<NodeBase> element_type; ns.insert(element_type(new NodeType(0,10))); // 0 = id, 10 = group_id ns.insert(element_type(new NodeType(1,10))); ns.insert(element_type(new NodeType(2,20))); // Now lets say I want to get a list of unique group_id values. // so I should get {10,20} event thought I have 3 elements //if i use the following for(index_t::const_iterator it=i.begin();it!=i.end();){ // note: no ++it // output the key std::cout<<i.key_extractor()(*it)<<std::endl; // jump to the next different key value ( which is great btw) it=i.upper_bound(i.key_extractor()(*it)); } //Note that the for loop still iterates 3 times and not 2 times. // Meaning that the results of the key_extractor()(*it) key_value are {10,10,20} // My goal is to get back just {10,20} and not {10,10,20} //assuming that in this non_unique_index container the key (group_id) is at least unique even though 10 points to 2 elements. return 0; } I hope I made my point this time. Regards Tal Agmon On 8/21/06, Joaquín Mª López Muñoz <joaquin@tid.es> wrote:
Tal Agmon ha escrito:
Hi Joaquin,
Sorry for the lack of info in my previous quote. I appreicate your affort to promptly help me.
What I have is a non_unique which I carry to get all the keys.( I don't care about the elements)
My guess is that key_extractor() returns a key_form_element, is quite redundant in my case.
Hello again.
Still I'm having difficulties with understanding your question, but let me try my hand: are you looking for a way to produce all *different* key values contained by an index? If so, something like the following would do:
for(index_t::const_iterator it=i.begin();it!=i.end();){ // note: no ++it // output the key std::cout<<i.key_extractor()(*it)<<std::endl;
// jump to the next different key value it=i.upper_bound(i.key_extractor()(*it)); }
Now, is this what you were asking about?
Regards Tal
Best,
Joaquín M López Muñoz Telefónica, Investigación y Desarrollo _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost