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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

    @mrjj it is a 'lidar tg15' sensor
    i did series->append(x, y);
    qDebug() << y;
    qDebug() << x;
    and I found all the points

    mrjjM Offline
    mrjjM Offline
    mrjj
    Lifetime Qt Champion
    wrote on last edited by
    #29

    @julie546
    Ok but the right diagram you showed the picture of.
    Did you hand draw this or did an app do it?

    since no points is missing im simply wondering if that data would allow the correct diagram at all.

    J 1 Reply Last reply
    0
    • mrjjM mrjj

      @julie546
      Ok but the right diagram you showed the picture of.
      Did you hand draw this or did an app do it?

      since no points is missing im simply wondering if that data would allow the correct diagram at all.

      J Offline
      J Offline
      julie546
      wrote on last edited by
      #30

      @mrjj 2.PNG
      it's from excel

      mrjjM 1 Reply Last reply
      0
      • J julie546

        @mrjj 2.PNG
        it's from excel

        mrjjM Offline
        mrjjM Offline
        mrjj
        Lifetime Qt Champion
        wrote on last edited by
        #31

        @julie546
        ok. and you used the same CSV file there ?

        and you compared the values we insert, value by value to make sure it reads as it should ?

        I mean if it could not convert for some reason it would silently continue.

         if(!ok)
           continue;
        

        some of the points to the far right seems more out there than on correct diagram.
        should be around 6.0 but is 6.8

        J 1 Reply Last reply
        2
        • mrjjM mrjj

          @julie546
          ok. and you used the same CSV file there ?

          and you compared the values we insert, value by value to make sure it reads as it should ?

          I mean if it could not convert for some reason it would silently continue.

           if(!ok)
             continue;
          

          some of the points to the far right seems more out there than on correct diagram.
          should be around 6.0 but is 6.8

          J Offline
          J Offline
          julie546
          wrote on last edited by
          #32

          @mrjj yes it's from the same csv file
          i have on the csv file 1500 value

          JonBJ 1 Reply Last reply
          0
          • J julie546

            @mrjj yes it's from the same csv file
            i have on the csv file 1500 value

            JonBJ Offline
            JonBJ Offline
            JonB
            wrote on last edited by
            #33

            @julie546
            As @mrjj said, just to humour us, in the two places you have

                    if(!ok)
                        continue;
            

            please put in above the if

            Q_ASSERT(ok);
            

            (You'll need to have included #include <QtGlobal>, but probably something else you are including will have done this.)

            KroMignonK 1 Reply Last reply
            1
            • JonBJ JonB

              @julie546
              As @mrjj said, just to humour us, in the two places you have

                      if(!ok)
                          continue;
              

              please put in above the if

              Q_ASSERT(ok);
              

              (You'll need to have included #include <QtGlobal>, but probably something else you are including will have done this.)

              KroMignonK Offline
              KroMignonK Offline
              KroMignon
              wrote on last edited by
              #34

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

              As @mrjj said, just to humour us, in the two places you have
              if(!ok)
              continue;

              please put in above the if
              Q_ASSERT(ok);

              The reason why there is continue, is because the CSV file contains the column headers, which are strings and cannot be converted to float.
              With Q_ASSERT() the program will be interrupted.

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

              mrjjM JonBJ 2 Replies Last reply
              1
              • KroMignonK KroMignon

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

                As @mrjj said, just to humour us, in the two places you have
                if(!ok)
                continue;

                please put in above the if
                Q_ASSERT(ok);

                The reason why there is continue, is because the CSV file contains the column headers, which are strings and cannot be converted to float.
                With Q_ASSERT() the program will be interrupted.

                mrjjM Offline
                mrjjM Offline
                mrjj
                Lifetime Qt Champion
                wrote on last edited by
                #35

                @KroMignon
                ah so it should skip first col. always. good catch.
                Im just wondering if all points really get converted as
                else i dont see how the graphs can be that differnt.

                1 Reply Last reply
                0
                • KroMignonK KroMignon

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

                  As @mrjj said, just to humour us, in the two places you have
                  if(!ok)
                  continue;

                  please put in above the if
                  Q_ASSERT(ok);

                  The reason why there is continue, is because the CSV file contains the column headers, which are strings and cannot be converted to float.
                  With Q_ASSERT() the program will be interrupted.

                  JonBJ Offline
                  JonBJ Offline
                  JonB
                  wrote on last edited by
                  #36

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

                  The reason why there is continue, is because the CSV file contains the column header

                  Surely that's for the first line only?

                  J 1 Reply Last reply
                  0
                  • JonBJ JonB

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

                    The reason why there is continue, is because the CSV file contains the column header

                    Surely that's for the first line only?

                    J Offline
                    J Offline
                    julie546
                    wrote on last edited by
                    #37

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

                    KroMignonK 1 Reply Last reply
                    0
                    • 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
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