Boost.Range

Range Adaptors


filtered

rng | boost::adaptors::filtered( pred )
boost::make_filtered_range( rng, pred )

Example

        #include <boost/range/adaptor/filtered.hpp>
        #include <boost/range/algorithm/copy.hpp>
        #include <boost/assign.hpp>
        #include <algorithm>
        #include <iostream>
        #include <vector>

        struct is_even
        {
            bool operator()(int x) const { return x % 2 == 0; }
        };
        
        int main(int argc, const char* argv[])
        {
            using namespace boost::assign;
            using namespace boost::adaptors;
            
            std::vector<int> input;
            input += 1,2,3,4,5,6,7,8,9;

            boost::copy(
                input | filtered(is_even()),
                std::ostream_iterator<int>(std::cout, ","));

            return 0;
        }
    

This would produce the output:
2,4,6,8


(C) Copyright Neil Groves 2009 (C) Copyright Thorsten Ottosen 2003-2004