{

        /*

         * Jeff --> Load xml.

         *          transform to Mat.

         * FileStorage.

         */

        cout << "loading the dataset...";

        // Step 1.

        FileStorage f;

        if(f.open(filename, FileStorage::READ))

        {

            // Step 2.

            f["datamat"] >> data;

            f["labelsmat"] >> labels;

            f.release();

        }

        else

        {

            cerr << "file can not be opened: " << filename << endl;

            return ;

        }

        // Step 3.

        data.convertTo(data, CV_32F);

        labels.convertTo(labels, CV_32F);

        cout << "read " << data.rows << " rows of data" << endl;

    }

read xml

/*this creates a yaml or xml list of files from the command line args

 */

#include "opencv2/core/core.hpp"

#include "opencv2/imgcodecs.hpp"

#include "opencv2/highgui/highgui.hpp"

#include <string>

#include <iostream>

using std::string;

using std::cout;

using std::endl;

using namespace cv;

static void help(char** av)

{

    cout << "\nThis creates a yaml or xml list of files from the command line args\n"

            "usage:\n./" << av[0] << " imagelist.yaml *.png\n"

         << "Try using different extensions.(e.g. yaml yml xml xml.gz etc...)\n"

         << "This will serialize this list of images or whatever with opencv's FileStorage framework" << endl;

}

int main(int ac, char** av)

{

    cv::CommandLineParser parser(ac, av, "{help h||}{@output||}");

    if (parser.has("help"))

    {

        help(av);

        return 0;

    }

    string outputname = parser.get<string>("@output");

    cout << "{yaml} outputname = " << outputname << endl;

    if (outputname.empty())

    {

        help(av);

        return 1;

    }

    Mat m = imread(outputname); //check if the output is an image - prevent overwrites!

    if(!m.empty()){

        std::cerr << "fail! Please specify an output file, don't want to overwrite you images!" << endl;

        help(av);

        return 1;

    }

    //Jeff --> write into outputname.

    FileStorage fs(outputname, FileStorage::WRITE);

    fs << "images" << "[";

    for(int i = 2; i < ac; i++){

        //Jeff --> write by "<<", redirection to file stream.

        fs << string(av[i]);

    }

    fs << "]";

    return 0;

}