Re: [Boost-users] Accessing an element of multi_index_container using iterator_to

2010/2/22 Andrew Kokkalis :

Declaration of my container is below: struct counterpart {     string word;     int id;     float tf_idf;

    counterpart(string word_, int id_) {

Prefer an initializer list: counterpart(string word, int id) : word(word), id(id), tf_idf(0.0) {}

};

typedef multi_index_container<     counterpart,     indexed_by<         ordered_unique<             tag, BOOST_MULTI_INDEX_MEMBER(counterpart, string, word)>,         ordered_unique<             tag, BOOST_MULTI_INDEX_MEMBER(counterpart, int, id)>,         ordered_non_unique<             tag, BOOST_MULTI_INDEX_MEMBER(counterpart, float, tf_idf)> >

...

word_index;

word_index word_set;

Each index of word_index acts/behaves like the corresponding STL container, and word_index "derives" from its first index so also behaves like it. So to search by word (first index), simply do a word_set.find() with a string. To search by any index, first get a *reference* to that index, e.g. word_set.get(), and then again use it according to its API. Set operations on ordered indexes are documented here: http://www.boost.org/doc/libs/1_41_0/libs/multi_index/doc/reference/ord_indi... Modifying elements is a little different, to allow the multi-index container to check them against all its indexes and possibly veto them, with optional commit/rollback semantic. I suggest you go thru the tutorial where all this is described. --DD