boost::adaptors::map_keys

References

Headers

boost::adaptors::map_keys is available by including any of the following headers:

  • boost/range/adaptor/map.hpp or
  • boost/range/adaptors.hpp

Examples

map_adaptors-pipe.cpp

#include <iostream>
#include <map>
#include <string>

#include <boost/algorithm/string/join.hpp>
#include <boost/range/adaptors.hpp>

const std::map<int, std::string> numbermap = {
    std::make_pair(1, "one"),
    std::make_pair(2, "two"),
    std::make_pair(3, "three"),
};


int main() {
    std::cout << "map keys: ";
    for (const auto & key : numbermap | boost::adaptors::map_keys) {
        std::cout << key << " ";
    }
    std::cout << std::endl;

    std::cout << "map values: "
              << boost::algorithm::join(numbermap | boost::adaptors::map_values, " ")
              << std::endl;

    return 0;
}

Output:

map keys: 1 2 3 
map values: one two three

 

Boost Range for Humans

This reference is part of Boost Range for Humans. Click the link to the overview.