Re: [Boost-users] converting value before inserting into a list

From: Flex Ferrum (flex_ferrum_at_[hidden])
Date: 2006-09-19 11:58:35

Hello, Alexander Shyrokov,

You wrote:
> I want to convert values according to a map before inserting it into the
> list. What is a proper way to do that?
> I have this:

> map<int,int> m;
> vector<int> a,b;

> for(vector<int>const_iterator i=a.begin();i!=a.end();++i)
>         b.push_back(m[*i]);

> I could use std::copy with std::back_inserter to add elements to b, but
> how do I convert it first? Should I write my own version of
> back_inserter for that?

> copy(a.begin(),a.end(),my_back_inserter(b,m));

> Thanks.

Try this:

#include <boost/lambda/lambda.hpp>

using namespace boost;
using namespace boost::lambda;

//...
//...

map<int,int> m;
vector<int> a,b;
std::transform(a.begin(), a.end(), std::back_inserter(b), var(m)[_1]);

Flex