Re: [Boost-users] how to lisk unique keys in boost multi_index_container

Subject: Re: [Boost-users] how to lisk unique keys in boost multi_index_container
From: Joaquin M Lopez Munoz (joaquin_at_[hidden])
Date: 2014-12-02 12:43:16

Bill Tian <billtian945 <at> gmail.com> writes:

> 
> hello,every one
> now i have a struct like this
> 
> struct a {
> a(const std::string &m1_, const std::string &m2_, boost::int16_t m3_)
> : m1(m1_),m2(m2_), m3(m3_) {}
> std::string m1;
> std::string m2;
> 
> boost::int16_t m3;
> };
>
> [...]
> 
> i want to get all data that m2 equal to "k1", when this data has been
> processed, get all data that m2 equal to "k2" ... but i do not how many
> unique keys in the container, am i need to store another set to store
> that when i fill the container? i need a function to get the keys
> like the SQL:"select distinct(m2) from data".

Something like that will do?

  for(auto it=data.get<1>().begin(),it_end=data.get<1>().end();
      it!=it_end;
      it=data.get<1>().upper_bound(it->m2)){
     std::cout<<it->m2<<"\n"; // or whatever you need to do with the key
  }

Hope this helps,

Joaquín M López Muñoz
Telefónica