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  4. how i can identify and read the columns of a csv file ?
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how i can identify and read the columns of a csv file ?

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  • J julie546

    @JonB @mrjj @KroMignon
    I remove the headers and I replace
    if (! ok)
    continue;
    by Q_ASSERT (ok);
    but it's the same result

    KroMignonK Offline
    KroMignonK Offline
    KroMignon
    wrote on last edited by
    #38

    @julie546 said in how i can identify and read the columns of a csv file ?:

    I remove the headers and I replace
    if (! ok)
    continue;
    by Q_ASSERT (ok);
    but it's the same result

    I suppose it is a simple precision issue, you should replace toFloat() with toDouble():

    while (!filelidar.atEnd()) {
        QString line = filelidar.readLine();
        const auto parts = line.split (',');
        if(parts.size() >= 2)
        {
            bool ok;
            qreal x = parts.at(0).toDouble(&ok);
            if(!ok)
            {
                qDebug() << "Could not parse X value" << parts.at(0);
                continue;
            }
            qreal y = parts.at(1).toDouble(&ok);
            if(!ok)
            {
                qDebug() << "Could not parse Y value" << parts.at(1);
                continue;
            }
            series->append(x, y);
        }
    }
    

    It is an old maxim of mine that when you have excluded the impossible, whatever remains, however improbable, must be the truth. (Sherlock Holmes)

    J 1 Reply Last reply
    0
    • KroMignonK KroMignon

      @julie546 said in how i can identify and read the columns of a csv file ?:

      I remove the headers and I replace
      if (! ok)
      continue;
      by Q_ASSERT (ok);
      but it's the same result

      I suppose it is a simple precision issue, you should replace toFloat() with toDouble():

      while (!filelidar.atEnd()) {
          QString line = filelidar.readLine();
          const auto parts = line.split (',');
          if(parts.size() >= 2)
          {
              bool ok;
              qreal x = parts.at(0).toDouble(&ok);
              if(!ok)
              {
                  qDebug() << "Could not parse X value" << parts.at(0);
                  continue;
              }
              qreal y = parts.at(1).toDouble(&ok);
              if(!ok)
              {
                  qDebug() << "Could not parse Y value" << parts.at(1);
                  continue;
              }
              series->append(x, y);
          }
      }
      
      J Offline
      J Offline
      julie546
      wrote on last edited by
      #39

      @KroMignon thank you for your answer you helped me a lot,I tried it but it's the same thing, you don't think it's about this instruction ?
      QScatterSeries * series = new QScatterSeries;
      series->setMarkerShape(QScatterSeries::MarkerShapeRectangle);

      KroMignonK JonBJ 2 Replies Last reply
      0
      • J julie546

        @mrjj
        thank you for your reply I have changed it but there are some missing points3.PNG
        QScatterSeries * series = new QScatterSeries;
        series->setMarkerShape(QScatterSeries::MarkerShapeRectangle);

        S Offline
        S Offline
        SimonSchroeder
        wrote on last edited by
        #40

        @julie546 said in how i can identify and read the columns of a csv file ?:

        thank you for your reply I have changed it but there are some missing points

        I am not sure that these points are actually missing. As far as I can tell you draw the points as blue squares with a white border (on a white background). If you look closely a lot of points are almost vanishing in the drawing (and some will vanish altogether). This is because the points are to close together (and some unfortunate pattern in your data) that the points overlap excactly so that you only see the white border of neighboring points (actually you don't see them as they are white on white). This makes it seem as if the points are missing.

        Try changing either the background color or the color of the borders of the data points. Or remove the border to be comparable to Excel (if that is what you want). I can't help you with the right functions as I have never used these charts.

        1 Reply Last reply
        0
        • J julie546

          @KroMignon thank you for your answer you helped me a lot,I tried it but it's the same thing, you don't think it's about this instruction ?
          QScatterSeries * series = new QScatterSeries;
          series->setMarkerShape(QScatterSeries::MarkerShapeRectangle);

          KroMignonK Offline
          KroMignonK Offline
          KroMignon
          wrote on last edited by
          #41

          @julie546 said in how i can identify and read the columns of a csv file ?:

          series->setMarkerShape(QScatterSeries::MarkerShapeRectangle);

          This will only change the way the point is draw (https://doc.qt.io/qt-5/qscatterseries.html#markerShape-prop).
          I don't think this will change anything.

          Are you sure you have exported all points in your CSV file?
          For me, it looks like positions are missed.

          It is an old maxim of mine that when you have excluded the impossible, whatever remains, however improbable, must be the truth. (Sherlock Holmes)

          1 Reply Last reply
          0
          • J julie546

            @KroMignon thank you for your answer you helped me a lot,I tried it but it's the same thing, you don't think it's about this instruction ?
            QScatterSeries * series = new QScatterSeries;
            series->setMarkerShape(QScatterSeries::MarkerShapeRectangle);

            JonBJ Offline
            JonBJ Offline
            JonB
            wrote on last edited by JonB
            #42

            @julie546
            Your example currently has "many" points. Like anything you are trying to develop/debug, can't you cut down to something with as few points as possible while you get going? Can you go back to your original master and have like, dunno, half a dozen points (or start from 2?!), and compare how that is supposed to look against what you're getting in Qt Charts? That would eliminate all this discussion about whether you have the same number of points and whether it's just a coloring/display issue, or whatever.

            1 Reply Last reply
            1
            • J Offline
              J Offline
              julie546
              wrote on last edited by
              #43

              it is not a problem of color nor of value because I have checked the numbers of values ​​and it is the same with the csv file and I have changed the color but it is the same graph

              JonBJ 1 Reply Last reply
              0
              • J julie546

                it is not a problem of color nor of value because I have checked the numbers of values ​​and it is the same with the csv file and I have changed the color but it is the same graph

                JonBJ Offline
                JonBJ Offline
                JonB
                wrote on last edited by JonB
                #44

                @julie546
                I still think it would help you and those trying to answer if you can reproduce a problem/difference with the absolute minimum of points to consider. Up to you.....

                J 1 Reply Last reply
                0
                • JonBJ JonB

                  @julie546
                  I still think it would help you and those trying to answer if you can reproduce a problem/difference with the absolute minimum of points to consider. Up to you.....

                  J Offline
                  J Offline
                  julie546
                  wrote on last edited by
                  #45

                  @JonB how i can change please the color of the window to black ?

                  Pl45m4P 1 Reply Last reply
                  0
                  • J Offline
                    J Offline
                    julie546
                    wrote on last edited by
                    #46

                    I tested this code but it did not change the color
                    QMainWindow window;
                    window.setCentralWidget(chartView);
                    window.resize(1000, 900);
                    window.setStyleSheet("QMainWindow {background: 'black';}");

                                           window.show(); 
                    

                    can you help me please

                    JonBJ 1 Reply Last reply
                    0
                    • J julie546

                      @JonB how i can change please the color of the window to black ?

                      Pl45m4P Offline
                      Pl45m4P Offline
                      Pl45m4
                      wrote on last edited by
                      #47

                      @julie546 said in how i can identify and read the columns of a csv file ?:

                      how i can change please the color of the window to black ?

                      https://doc.qt.io/qt-5/qtcharts-customchart-example.html

                      If you want the QChartbackground to be black, try

                      chart->setBackgroundBrush(QBrush(Qt::Black));
                      

                      For QMainWindow:

                      window.setStyleSheet("QMainWindow { background-color: black }");
                      
                      

                      If debugging is the process of removing software bugs, then programming must be the process of putting them in.

                      ~E. W. Dijkstra

                      1 Reply Last reply
                      2
                      • J julie546

                        I tested this code but it did not change the color
                        QMainWindow window;
                        window.setCentralWidget(chartView);
                        window.resize(1000, 900);
                        window.setStyleSheet("QMainWindow {background: 'black';}");

                                               window.show(); 
                        

                        can you help me please

                        JonBJ Offline
                        JonBJ Offline
                        JonB
                        wrote on last edited by
                        #48

                        @julie546
                        Try removing the quotes, window.setStyleSheet("QMainWindow {background: black;}");, and also you may need instead window.setStyleSheet("QMainWindow {background-color: black;}");?

                        1 Reply Last reply
                        1
                        • J Offline
                          J Offline
                          julie546
                          wrote on last edited by
                          #49

                          I solved the problem thank you for helping me it was because of the color
                          @JonB @J-Hilk @KroMignon @Pl45m4 @SimonSchroeder

                          1 Reply Last reply
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