Boost C++ Libraries

...one of the most highly regarded and expertly designed C++ library projects in the world. — Herb Sutter and Andrei Alexandrescu, C++ Coding Standards

map_values

map_values

map_values example

Syntax	Code
Pipe	`rng \| boost::adaptors::map_values`
Function	`boost::adaptors::values(rng)`

Precondition: The value_type of the range is an instantiation of std::pair.
Postcondition: For all elements x in the returned range, x is the result of y.second where y is the corresponding element in the original range.
Range Category: Single Pass Range
Range Return Type: for constant ranges, boost::select_second_const<typeof(rng)> otherwise boost:select_second_mutable<typeof(rng)>
Returned Range Category: The range category of rng.

map_values example

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

int main(int argc, const char* argv[])
{
    using namespace boost::assign;
    using namespace boost::adaptors;

    std::map<int,int> input;
    for (int i = 0; i < 10; ++i)
        input.insert(std::make_pair(i, i * 10));

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

    return 0;
}

This would produce the output:

0,10,20,30,40,50,60,70,80,90