histogram/examples/guide_fill_histogram.cpp

//[ guide_fill_histogram

#include <boost/histogram.hpp>
#include <vector>
#include <utility>

namespace bh = boost::histogram;

int main() {
    auto h = bh::make_static_histogram(bh::axis::integer<>(0, 4),
                                       bh::axis::regular<>(10, 0, 5));

    // fill histogram, number of arguments must be equal to number of axes
    h(0, 1.1); // increases bin counter by one
    h(bh::weight(2), 3, 3.4); // increase bin counter by 2 instead of 1

    // histogram also supports fills from a container of values; a container
    // of wrong size trips an assertion in debug mode
    auto xy1 = std::make_pair(4, 3.1);
    h(xy1);
    auto xy2 = std::vector<double>({3.0, 4.9});
    h(xy2);

    // functional-style processing is also supported
    std::vector<std::pair<int, double>> input_data{
        {0, 1.2}, {2, 3.4}, {4, 5.6}
    };
    // Note that std::for_each takes the functor by value, thus it makes a
    // potentially expensive copy of your histogram. Passing freshly created
    // histograms is ok, though, because of return-value-optimization
    auto h2 = std::for_each(input_data.begin(), input_data.end(),
                            bh::make_static_histogram(
                              bh::axis::integer<>(0, 4),
                              bh::axis::regular<>(10, 0, 5)));
    // h is filled
}

//]