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How to retrieve data from an excel .csv file, and put it in a graph with QCustomPlot

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  • S SimonSchroeder

    .csv files are just simple text files. If you have simple data in them, writing a parser is quite simple. (Just as @jsulm said: splitting is enough.) It gets a little bit more complicated if not all of your users are using the English setting for exporting .csv files. In Germany, for example, we use a comma for the decimal point and hence a semicolon to separate columns. If you have text in some cells it can even get a little bit more tricky because text might contain commas as well (text will then be escaped in double quotes).

    So, as long as you just have numbers in your .csv file, go with the simple route mentioned by @jsulm.

    R Offline
    R Offline
    Raphawel
    wrote on last edited by
    #4

    @SimonSchroeder For example I have this in my .csv file:

    Date/Time;Power Consumed (W);Energy Consumed (Wh);Cumulative Energy Consumed (Wh)
    09/21/2022 02:45 PM CEST;2,712;674;1,25
    09/21/2022 03:00 PM CEST;2,652;-866;384
    09/21/2022 03:15 PM CEST;240;1,088;1,472
    09/21/2022 03:30 PM CEST;120;38;1,51
    09/21/2022 03:45 PM CEST;132;33;1,543
    09/21/2022 04:00 PM CEST;156;52;1,595
    09/21/2022 04:15 PM CEST;132;33;1,628
    09/21/2022 04:30 PM CEST;228;46;1,674
    09/21/2022 04:45 PM CEST;144;38;1,712
    09/21/2022 05:00 PM CEST;168;36;1,748
    09/21/2022 05:15 PM CEST;144;50;1,798
    09/21/2022 05:30 PM CEST;144;35;1,833
    09/21/2022 05:45 PM CEST;240;50;1,883
    09/21/2022 06:00 PM CEST;132;35;1,918
    09/21/2022 06:15 PM CEST;168;31;1,949
    09/21/2022 06:30 PM CEST;84;33;1,982
    09/21/2022 06:45 PM CEST;96;23;2,005
    09/21/2022 07:00 PM CEST;132;38;2,043
    09/21/2022 07:15 PM CEST;84;22;2,065
    09/21/2022 07:30 PM CEST;192;48;2,113
    09/21/2022 07:45 PM CEST;132;32;2,145
    09/21/2022 08:00 PM CEST;1,08;156;2,301
    09/21/2022 08:15 PM CEST;168;102;2,403
    09/21/2022 08:30 PM CEST;264;50;2,453
    09/21/2022 08:45 PM CEST;156;45;2,498
    09/21/2022 09:00 PM CEST;216;45;2,543
    09/21/2022 09:15 PM CEST;156;48;2,591
    09/21/2022 09:30 PM CEST;216;44;2,635
    09/21/2022 09:45 PM CEST;156;51;2,686
    09/21/2022 10:00 PM CEST;180;40;2,726
    

    So it's the same for me, i use comma for the decimal and a semicolon to separate columns

    JonBJ 1 Reply Last reply
    0
    • R Raphawel

      @SimonSchroeder For example I have this in my .csv file:

      Date/Time;Power Consumed (W);Energy Consumed (Wh);Cumulative Energy Consumed (Wh)
      09/21/2022 02:45 PM CEST;2,712;674;1,25
      09/21/2022 03:00 PM CEST;2,652;-866;384
      09/21/2022 03:15 PM CEST;240;1,088;1,472
      09/21/2022 03:30 PM CEST;120;38;1,51
      09/21/2022 03:45 PM CEST;132;33;1,543
      09/21/2022 04:00 PM CEST;156;52;1,595
      09/21/2022 04:15 PM CEST;132;33;1,628
      09/21/2022 04:30 PM CEST;228;46;1,674
      09/21/2022 04:45 PM CEST;144;38;1,712
      09/21/2022 05:00 PM CEST;168;36;1,748
      09/21/2022 05:15 PM CEST;144;50;1,798
      09/21/2022 05:30 PM CEST;144;35;1,833
      09/21/2022 05:45 PM CEST;240;50;1,883
      09/21/2022 06:00 PM CEST;132;35;1,918
      09/21/2022 06:15 PM CEST;168;31;1,949
      09/21/2022 06:30 PM CEST;84;33;1,982
      09/21/2022 06:45 PM CEST;96;23;2,005
      09/21/2022 07:00 PM CEST;132;38;2,043
      09/21/2022 07:15 PM CEST;84;22;2,065
      09/21/2022 07:30 PM CEST;192;48;2,113
      09/21/2022 07:45 PM CEST;132;32;2,145
      09/21/2022 08:00 PM CEST;1,08;156;2,301
      09/21/2022 08:15 PM CEST;168;102;2,403
      09/21/2022 08:30 PM CEST;264;50;2,453
      09/21/2022 08:45 PM CEST;156;45;2,498
      09/21/2022 09:00 PM CEST;216;45;2,543
      09/21/2022 09:15 PM CEST;156;48;2,591
      09/21/2022 09:30 PM CEST;216;44;2,635
      09/21/2022 09:45 PM CEST;156;51;2,686
      09/21/2022 10:00 PM CEST;180;40;2,726
      

      So it's the same for me, i use comma for the decimal and a semicolon to separate columns

      JonBJ Online
      JonBJ Online
      JonB
      wrote on last edited by
      #5

      @Raphawel
      Since you don't have to worry about any " (double quote) around your items you can just use QString::split() with the ; character to split into fields/columns. Your , for floating point numbers can be dealt with by a suitable "to number/float" which allows for your locale, either in QString or QLocale classes, have a look through.

      R 1 Reply Last reply
      3
      • JonBJ JonB

        @Raphawel
        Since you don't have to worry about any " (double quote) around your items you can just use QString::split() with the ; character to split into fields/columns. Your , for floating point numbers can be dealt with by a suitable "to number/float" which allows for your locale, either in QString or QLocale classes, have a look through.

        R Offline
        R Offline
        Raphawel
        wrote on last edited by
        #6

        @JonB Ok thanks :) , and just to be sure it applies for the QT 5.6.3 version? Because I need to use this one for a project

        JonBJ 1 Reply Last reply
        0
        • R Raphawel

          @JonB Ok thanks :) , and just to be sure it applies for the QT 5.6.3 version? Because I need to use this one for a project

          JonBJ Online
          JonBJ Online
          JonB
          wrote on last edited by
          #7

          @Raphawel This is quite independent of Qt version.

          R 1 Reply Last reply
          1
          • JonBJ JonB

            @Raphawel This is quite independent of Qt version.

            R Offline
            R Offline
            Raphawel
            wrote on last edited by Raphawel
            #8

            @JonB I'm trying to display items from a test.csv file in a QTableView. But I have a problem, my code works but I have the impression that it does'nt recognize the test.csv file even though it is in the project folder of the code.

            This is obvious because I don't receive any value in my QTableView. And even when I do a debug

            This is my test.csv:

            24adddf7-0384-4f9d-91a4-e2e92313062b-image.png

            And my program :

            void MainWindow::LireFichierCSV()
            {
            
                QStandardItemModel *model= new QStandardItemModel();
                QFile file("test.csv");    //My CSV
            
                if(file.open(QFile::ReadOnly) | QIODevice::Text)
                {
                int lineindex = 0;
                QTextStream flux(&file);
            
                while(!flux.atEnd())
                {
                    QString ligne = flux.readLine();
                    QStringList champs = ligne.split(";", QString::SkipEmptyParts);
            
                    for(int j=0;j < champs.size();j++)
                    {
                        QString value = champs.at(j);
                        QStandardItem *item = new QStandardItem(value);
                        model->setItem(lineindex, j, item);
                    }
                    lineindex++;
            
                }
                    file.close();
                    ui->tableView->setModel(model);
            
                }  
            }
            

            And this is my result with debug :

            156d8900-a88d-4ac1-8d21-8bb8693b4ac2-image.png

            S JonBJ 2 Replies Last reply
            0
            • R Raphawel

              @JonB I'm trying to display items from a test.csv file in a QTableView. But I have a problem, my code works but I have the impression that it does'nt recognize the test.csv file even though it is in the project folder of the code.

              This is obvious because I don't receive any value in my QTableView. And even when I do a debug

              This is my test.csv:

              24adddf7-0384-4f9d-91a4-e2e92313062b-image.png

              And my program :

              void MainWindow::LireFichierCSV()
              {
              
                  QStandardItemModel *model= new QStandardItemModel();
                  QFile file("test.csv");    //My CSV
              
                  if(file.open(QFile::ReadOnly) | QIODevice::Text)
                  {
                  int lineindex = 0;
                  QTextStream flux(&file);
              
                  while(!flux.atEnd())
                  {
                      QString ligne = flux.readLine();
                      QStringList champs = ligne.split(";", QString::SkipEmptyParts);
              
                      for(int j=0;j < champs.size();j++)
                      {
                          QString value = champs.at(j);
                          QStandardItem *item = new QStandardItem(value);
                          model->setItem(lineindex, j, item);
                      }
                      lineindex++;
              
                  }
                      file.close();
                      ui->tableView->setModel(model);
              
                  }  
              }
              

              And this is my result with debug :

              156d8900-a88d-4ac1-8d21-8bb8693b4ac2-image.png

              S Offline
              S Offline
              SimonSchroeder
              wrote on last edited by
              #9

              @Raphawel Got to "Projects" on the left pane and check the run configuration. Is your file test.csv inside the folder that is set as working directory? You can adapt the working directory to your needs if necessary.

              1 Reply Last reply
              1
              • R Raphawel

                @JonB I'm trying to display items from a test.csv file in a QTableView. But I have a problem, my code works but I have the impression that it does'nt recognize the test.csv file even though it is in the project folder of the code.

                This is obvious because I don't receive any value in my QTableView. And even when I do a debug

                This is my test.csv:

                24adddf7-0384-4f9d-91a4-e2e92313062b-image.png

                And my program :

                void MainWindow::LireFichierCSV()
                {
                
                    QStandardItemModel *model= new QStandardItemModel();
                    QFile file("test.csv");    //My CSV
                
                    if(file.open(QFile::ReadOnly) | QIODevice::Text)
                    {
                    int lineindex = 0;
                    QTextStream flux(&file);
                
                    while(!flux.atEnd())
                    {
                        QString ligne = flux.readLine();
                        QStringList champs = ligne.split(";", QString::SkipEmptyParts);
                
                        for(int j=0;j < champs.size();j++)
                        {
                            QString value = champs.at(j);
                            QStandardItem *item = new QStandardItem(value);
                            model->setItem(lineindex, j, item);
                        }
                        lineindex++;
                
                    }
                        file.close();
                        ui->tableView->setModel(model);
                
                    }  
                }
                

                And this is my result with debug :

                156d8900-a88d-4ac1-8d21-8bb8693b4ac2-image.png

                JonBJ Online
                JonBJ Online
                JonB
                wrote on last edited by JonB
                #10

                @Raphawel said in How to retrieve data from an excel .csv file, and put it in a graph with QCustomPlot:

                QFile file("test.csv"); //My CSV

                Do not use a relative path like this. It means relative to whatever the current working directory is, and you really don't know what that will be at runtime. Use an absolute path, or build a path from QStandardPaths. Your "project folder" does not "exist" at runtime, it's purely something that is used by Creator at design time.

                R 1 Reply Last reply
                3
                • SGaistS Offline
                  SGaistS Offline
                  SGaist
                  Lifetime Qt Champion
                  wrote on last edited by
                  #11

                  Hi,

                  In addition to what my fellows wrote: add menu and or button to allow your user to browse their system to the .CSV file so you don't have to hard code any value.

                  You can use QFileDialog for that.

                  Interested in AI ? www.idiap.ch
                  Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

                  R 1 Reply Last reply
                  2
                  • JonBJ JonB

                    @Raphawel said in How to retrieve data from an excel .csv file, and put it in a graph with QCustomPlot:

                    QFile file("test.csv"); //My CSV

                    Do not use a relative path like this. It means relative to whatever the current working directory is, and you really don't know what that will be at runtime. Use an absolute path, or build a path from QStandardPaths. Your "project folder" does not "exist" at runtime, it's purely something that is used by Creator at design time.

                    R Offline
                    R Offline
                    Raphawel
                    wrote on last edited by
                    #12

                    @JonB

                    I followed your advice and did this:

                    QStringList location = QStandardPaths::standardLocations(QStandardPaths::DocumentsLocation);
                    QString result = location[0];
                    result = result + QString("/test.csv");
                    QFile file(result);
                    

                    I don't know if this is exactly what you are thinking about but if I understand correctly, here we come to look at the /Document directory and come to read all the files that are in it. And it works

                    1 Reply Last reply
                    1
                    • SGaistS SGaist

                      Hi,

                      In addition to what my fellows wrote: add menu and or button to allow your user to browse their system to the .CSV file so you don't have to hard code any value.

                      You can use QFileDialog for that.

                      R Offline
                      R Offline
                      Raphawel
                      wrote on last edited by
                      #13

                      @SGaist Excuse me, I'm not sure I understand what you're telling me.

                      Right now I am practicing retrieving values from a .CSV. This is not the actual .csv file that I will eventually use.

                      And normally, in the real application, the user will only be able to see the values from a graph that will display the values in real time.

                      Does this apply to what you mean?

                      jsulmJ 1 Reply Last reply
                      0
                      • R Raphawel

                        @SGaist Excuse me, I'm not sure I understand what you're telling me.

                        Right now I am practicing retrieving values from a .CSV. This is not the actual .csv file that I will eventually use.

                        And normally, in the real application, the user will only be able to see the values from a graph that will display the values in real time.

                        Does this apply to what you mean?

                        jsulmJ Offline
                        jsulmJ Offline
                        jsulm
                        Lifetime Qt Champion
                        wrote on last edited by
                        #14

                        @Raphawel @SGaist suggested to provide the user the posibility to open a CSV file, just like in any other application using, for example, "File/Open" menu. But this is of course only needed if you want to give the users of your application a possibility to open a CSV file.

                        https://forum.qt.io/topic/113070/qt-code-of-conduct

                        R 1 Reply Last reply
                        1
                        • jsulmJ jsulm

                          @Raphawel @SGaist suggested to provide the user the posibility to open a CSV file, just like in any other application using, for example, "File/Open" menu. But this is of course only needed if you want to give the users of your application a possibility to open a CSV file.

                          R Offline
                          R Offline
                          Raphawel
                          wrote on last edited by Raphawel
                          #15

                          @jsulm Oh right, so I don't think it will be useful for my application.

                          Just to show my result:
                          CSV used:

                          Date/Time;Power Consumed (W);Energy Consumed (Wh);Cumulative Energy Consumed (Wh)
                          09/21/2022 02:30 PM CEST;;;576
                          09/21/2022 02:45 PM CEST;2,712;674;1,25
                          09/21/2022 03:00 PM CEST;2,652;-866;384
                          09/21/2022 03:15 PM CEST;240;1,088;1,472
                          09/21/2022 03:30 PM CEST;120;38;1,51
                          09/21/2022 03:45 PM CEST;132;33;1,543
                          09/21/2022 04:00 PM CEST;156;52;1,595
                          09/21/2022 04:15 PM CEST;132;33;1,628
                          09/21/2022 04:30 PM CEST;228;46;1,674
                          09/21/2022 04:45 PM CEST;144;38;1,712
                          09/21/2022 05:00 PM CEST;168;36;1,748
                          09/21/2022 05:15 PM CEST;144;50;1,798
                          09/21/2022 05:30 PM CEST;144;35;1,833
                          09/21/2022 05:45 PM CEST;240;50;1,883
                          09/21/2022 06:00 PM CEST;132;35;1,918
                          09/21/2022 06:15 PM CEST;168;31;1,949
                          09/21/2022 06:30 PM CEST;84;33;1,982
                          09/21/2022 06:45 PM CEST;96;23;2,005
                          09/21/2022 07:00 PM CEST;132;38;2,043
                          09/21/2022 07:15 PM CEST;84;22;2,065
                          09/21/2022 07:30 PM CEST;192;48;2,113
                          09/21/2022 07:45 PM CEST;132;32;2,145
                          09/21/2022 08:00 PM CEST;1,08;156;2,301
                          09/21/2022 08:15 PM CEST;168;102;2,403
                          09/21/2022 08:30 PM CEST;264;50;2,453
                          09/21/2022 08:45 PM CEST;156;45;2,498
                          09/21/2022 09:00 PM CEST;216;45;2,543
                          09/21/2022 09:15 PM CEST;156;48;2,591
                          09/21/2022 09:30 PM CEST;216;44;2,635
                          09/21/2022 09:45 PM CEST;156;51;2,686
                          09/21/2022 10:00 PM CEST;180;40;2,726
                          09/21/2022 10:15 PM CEST;144;49;2,775
                          09/21/2022 10:30 PM CEST;132;30;2,805
                          09/21/2022 10:45 PM CEST;108;42;2,847
                          09/21/2022 11:00 PM CEST;108;25;2,872
                          09/21/2022 11:15 PM CEST;108;43;2,915
                          

                          Code (To identify the empty fields, I replaced :

                          QStringList champs = ligne.split(";",QString::SkipEmptyParts);
                          

                          by :

                          QStringList champs = ligne.split(";", QString::KeepEmptyParts);
                          

                          Code :

                          void MainWindow::LireFichierCSV()
                          {
                          
                              QStandardItemModel *model= new QStandardItemModel();
                          
                              QStringList location = QStandardPaths::standardLocations(QStandardPaths::DocumentsLocation);  // Viens lire tout les fichiers du répertoire Document, mettre ::DesktopLocation pour le bureau
                              QString result = location[0];
                              result = result + QString("/system_meter_conso.csv");
                              QFile file(result);
                          
                              if(file.open(QFile::ReadOnly) | QIODevice::Text)
                              {
                          
                              model->setHorizontalHeaderLabels(QStringList() << "Date/Time" << "PowerConsumed (W)");
                          
                              int lineindex = 0;
                              QTextStream flux(&file);
                          
                               flux.readLineInto(nullptr); // Passe la 1ère ligne
                          
                              while(!flux.atEnd())
                              {
                                  QString ligne = flux.readLine();
                                  QStringList champs = ligne.split(";", QString::KeepEmptyParts); //::KeepEmptyParts : Permet de voir les zones vides et de noter les résultats que quand il y en a
                          
                                  for(int j=0;j < champs.size();j++)
                                  {
                                      QString value = champs.at(j);
                                      QStandardItem *item = new QStandardItem(value);
                                      model->setItem(lineindex, j, item);
                                  }
                                  lineindex++;
                              }
                          
                              file.close();
                          
                                  ui->tableView->setModel(model);
                              }
                          }
                          

                          Result:

                          31ad259f-b99b-4a51-a8f2-459cbbea5b0a-image.png

                          Now my goal is to recover only the first two columns

                          R 1 Reply Last reply
                          0
                          • R Raphawel

                            @jsulm Oh right, so I don't think it will be useful for my application.

                            Just to show my result:
                            CSV used:

                            Date/Time;Power Consumed (W);Energy Consumed (Wh);Cumulative Energy Consumed (Wh)
                            09/21/2022 02:30 PM CEST;;;576
                            09/21/2022 02:45 PM CEST;2,712;674;1,25
                            09/21/2022 03:00 PM CEST;2,652;-866;384
                            09/21/2022 03:15 PM CEST;240;1,088;1,472
                            09/21/2022 03:30 PM CEST;120;38;1,51
                            09/21/2022 03:45 PM CEST;132;33;1,543
                            09/21/2022 04:00 PM CEST;156;52;1,595
                            09/21/2022 04:15 PM CEST;132;33;1,628
                            09/21/2022 04:30 PM CEST;228;46;1,674
                            09/21/2022 04:45 PM CEST;144;38;1,712
                            09/21/2022 05:00 PM CEST;168;36;1,748
                            09/21/2022 05:15 PM CEST;144;50;1,798
                            09/21/2022 05:30 PM CEST;144;35;1,833
                            09/21/2022 05:45 PM CEST;240;50;1,883
                            09/21/2022 06:00 PM CEST;132;35;1,918
                            09/21/2022 06:15 PM CEST;168;31;1,949
                            09/21/2022 06:30 PM CEST;84;33;1,982
                            09/21/2022 06:45 PM CEST;96;23;2,005
                            09/21/2022 07:00 PM CEST;132;38;2,043
                            09/21/2022 07:15 PM CEST;84;22;2,065
                            09/21/2022 07:30 PM CEST;192;48;2,113
                            09/21/2022 07:45 PM CEST;132;32;2,145
                            09/21/2022 08:00 PM CEST;1,08;156;2,301
                            09/21/2022 08:15 PM CEST;168;102;2,403
                            09/21/2022 08:30 PM CEST;264;50;2,453
                            09/21/2022 08:45 PM CEST;156;45;2,498
                            09/21/2022 09:00 PM CEST;216;45;2,543
                            09/21/2022 09:15 PM CEST;156;48;2,591
                            09/21/2022 09:30 PM CEST;216;44;2,635
                            09/21/2022 09:45 PM CEST;156;51;2,686
                            09/21/2022 10:00 PM CEST;180;40;2,726
                            09/21/2022 10:15 PM CEST;144;49;2,775
                            09/21/2022 10:30 PM CEST;132;30;2,805
                            09/21/2022 10:45 PM CEST;108;42;2,847
                            09/21/2022 11:00 PM CEST;108;25;2,872
                            09/21/2022 11:15 PM CEST;108;43;2,915
                            

                            Code (To identify the empty fields, I replaced :

                            QStringList champs = ligne.split(";",QString::SkipEmptyParts);
                            

                            by :

                            QStringList champs = ligne.split(";", QString::KeepEmptyParts);
                            

                            Code :

                            void MainWindow::LireFichierCSV()
                            {
                            
                                QStandardItemModel *model= new QStandardItemModel();
                            
                                QStringList location = QStandardPaths::standardLocations(QStandardPaths::DocumentsLocation);  // Viens lire tout les fichiers du répertoire Document, mettre ::DesktopLocation pour le bureau
                                QString result = location[0];
                                result = result + QString("/system_meter_conso.csv");
                                QFile file(result);
                            
                                if(file.open(QFile::ReadOnly) | QIODevice::Text)
                                {
                            
                                model->setHorizontalHeaderLabels(QStringList() << "Date/Time" << "PowerConsumed (W)");
                            
                                int lineindex = 0;
                                QTextStream flux(&file);
                            
                                 flux.readLineInto(nullptr); // Passe la 1ère ligne
                            
                                while(!flux.atEnd())
                                {
                                    QString ligne = flux.readLine();
                                    QStringList champs = ligne.split(";", QString::KeepEmptyParts); //::KeepEmptyParts : Permet de voir les zones vides et de noter les résultats que quand il y en a
                            
                                    for(int j=0;j < champs.size();j++)
                                    {
                                        QString value = champs.at(j);
                                        QStandardItem *item = new QStandardItem(value);
                                        model->setItem(lineindex, j, item);
                                    }
                                    lineindex++;
                                }
                            
                                file.close();
                            
                                    ui->tableView->setModel(model);
                                }
                            }
                            

                            Result:

                            31ad259f-b99b-4a51-a8f2-459cbbea5b0a-image.png

                            Now my goal is to recover only the first two columns

                            R Offline
                            R Offline
                            Raphawel
                            wrote on last edited by Raphawel
                            #16

                            @Raphawel To recover the first two colums here is the program:

                            void MainWindow::LireFichierCSV()
                            {
                            
                                QStandardItemModel *model= new QStandardItemModel();
                                //QFile file("test.csv");
                            
                                QStringList location = QStandardPaths::standardLocations(QStandardPaths::DocumentsLocation);  // Viens lire tout les fichiers du répertoire Document, mettre ::DesktopLocation pour le bureau
                                QString result = location[0];
                                result = result + QString("/system_meter_conso.csv");
                                QFile file(result);
                            
                                if(file.open(QFile::ReadOnly) | QIODevice::Text)
                                {
                            
                                model->setHorizontalHeaderLabels(QStringList() << "Date/Time" << "PowerConsumed (W)");
                            
                                int lineindex = 0;
                                QTextStream flux(&file);
                            
                            
                            
                                 flux.readLineInto(nullptr); // Passe la 1ère ligne
                            
                                 QStringList lineList = {};
                                 QStringList columnList = {};
                            
                            
                            
                                while(!flux.atEnd())
                                {
                                       QString ligne = flux.readLine();
                                       QStringList champs = ligne.split(";", QString::KeepEmptyParts); //::KeepEmptyParts : Permet de voir les zones vides et de noter les résultats que quand il y en a
                            
                                       lineList.append(champs[0]);
                                       columnList.append(champs[1]);
                            
                            
                                        QString valueL = lineList[lineindex];
                                        QString valueC = columnList[lineindex];
                                        QStandardItem *itemL = new QStandardItem(valueL);
                                        QStandardItem *itemC = new QStandardItem(valueC);
                                        model->setItem(lineindex, 0, itemL );
                                        model->setItem(lineindex, 1,  itemC);
                                       lineindex++;
                            
                                    /*for(int j=0;j < champs.size();j++)
                                    {
                                        QString value = champs.at(j);
                                        QStandardItem *item = new QStandardItem(value);
                                        model->setItem(lineindex, j, item);
                                    }
                                    lineindex++;*/
                                }
                            
                                file.close();
                            
                                    ui->tableView->setModel(model);
                                }
                            
                            }
                            

                            Result:
                            576a0f0f-b4ed-4862-882c-7de650563d44-image.png

                            R 1 Reply Last reply
                            0
                            • R Raphawel

                              @Raphawel To recover the first two colums here is the program:

                              void MainWindow::LireFichierCSV()
                              {
                              
                                  QStandardItemModel *model= new QStandardItemModel();
                                  //QFile file("test.csv");
                              
                                  QStringList location = QStandardPaths::standardLocations(QStandardPaths::DocumentsLocation);  // Viens lire tout les fichiers du répertoire Document, mettre ::DesktopLocation pour le bureau
                                  QString result = location[0];
                                  result = result + QString("/system_meter_conso.csv");
                                  QFile file(result);
                              
                                  if(file.open(QFile::ReadOnly) | QIODevice::Text)
                                  {
                              
                                  model->setHorizontalHeaderLabels(QStringList() << "Date/Time" << "PowerConsumed (W)");
                              
                                  int lineindex = 0;
                                  QTextStream flux(&file);
                              
                              
                              
                                   flux.readLineInto(nullptr); // Passe la 1ère ligne
                              
                                   QStringList lineList = {};
                                   QStringList columnList = {};
                              
                              
                              
                                  while(!flux.atEnd())
                                  {
                                         QString ligne = flux.readLine();
                                         QStringList champs = ligne.split(";", QString::KeepEmptyParts); //::KeepEmptyParts : Permet de voir les zones vides et de noter les résultats que quand il y en a
                              
                                         lineList.append(champs[0]);
                                         columnList.append(champs[1]);
                              
                              
                                          QString valueL = lineList[lineindex];
                                          QString valueC = columnList[lineindex];
                                          QStandardItem *itemL = new QStandardItem(valueL);
                                          QStandardItem *itemC = new QStandardItem(valueC);
                                          model->setItem(lineindex, 0, itemL );
                                          model->setItem(lineindex, 1,  itemC);
                                         lineindex++;
                              
                                      /*for(int j=0;j < champs.size();j++)
                                      {
                                          QString value = champs.at(j);
                                          QStandardItem *item = new QStandardItem(value);
                                          model->setItem(lineindex, j, item);
                                      }
                                      lineindex++;*/
                                  }
                              
                                  file.close();
                              
                                      ui->tableView->setModel(model);
                                  }
                              
                              }
                              

                              Result:
                              576a0f0f-b4ed-4862-882c-7de650563d44-image.png

                              R Offline
                              R Offline
                              Raphawel
                              wrote on last edited by Raphawel
                              #17

                              Could someone help me please ? :(

                              void GraphConso::LireFichierCSV()
                              {
                                  QStandardItemModel *model= new QStandardItemModel();
                                  //QFile file("test.csv");
                              
                                  QStringList location = QStandardPaths::standardLocations(QStandardPaths::DocumentsLocation);  // Viens lire tout les fichiers du répertoire Document, mettre ::DesktopLocation pour le bureau
                                  QString result = location[0];
                                  result = result + QString("/system_meter_conso.csv");
                                  QFile file(result);
                              
                                  if(file.open(QFile::ReadOnly) | QIODevice::Text)
                                  {
                              
                                      model->setHorizontalHeaderLabels(QStringList() << "Date/Time" << "PowerConsumed (W)");
                              
                                      int lineindex = 0;
                                      QTextStream flux(&file);
                              
                              
                              
                                      flux.readLineInto(nullptr); // Passe la 1ère ligne
                              
                                      QStringList lineList = {};
                                      QStringList columnList = {};
                              
                              
                              
                                      while(!flux.atEnd())
                                      {
                                          QString ligne = flux.readLine();
                                          QStringList champs = ligne.split(";", QString::KeepEmptyParts); //::KeepEmptyParts : Permet de voir les zones vides et de noter les résultats que quand il y en a
                              
                                          lineList.append(champs[0]);
                                          columnList.append(champs[1]);
                                          ui->customplot->graph(0)->setData(lineList, columnList);
                                          ui->customplot->replot();
                              
                              
                                          QString valueL = lineList[lineindex];
                                          QString valueC = columnList[lineindex];
                                          QStandardItem *itemL = new QStandardItem(valueL);
                                          QStandardItem *itemC = new QStandardItem(valueC);
                                          model->setItem(lineindex, 0,  itemL);
                                          model->setItem(lineindex, 1,  itemC);
                              
                                          lineindex++;
                              
                                      }
                              
                                      file.close();
                              
                                      ui->tableView->setModel(model);
                              
                                  }
                              
                              }
                              

                              I would like to display on my graph, the values of the two columns with x -> Date/Time and y -> PowerConsumed.

                              Here I have used the rows :

                              ui->customplot->graph(0)->QCPGraph::setData(lineList, columnList);
                                         ui->customplot->replot();
                              

                              I still don't know if this technique works but I get this as an error:
                              Can you help me please ?

                              C:\Users\46053500\Documents\Graph_QT\graphConso\graphconso.cpp:122: erreur : 'QCPGraph' is not a base of 'QCustomPlot'
                                           ui->customplot->QCPGraph::setData(lineList, columnList);
                              

                              I don't know what this means

                              JonBJ 1 Reply Last reply
                              0
                              • R Raphawel

                                Could someone help me please ? :(

                                void GraphConso::LireFichierCSV()
                                {
                                    QStandardItemModel *model= new QStandardItemModel();
                                    //QFile file("test.csv");
                                
                                    QStringList location = QStandardPaths::standardLocations(QStandardPaths::DocumentsLocation);  // Viens lire tout les fichiers du répertoire Document, mettre ::DesktopLocation pour le bureau
                                    QString result = location[0];
                                    result = result + QString("/system_meter_conso.csv");
                                    QFile file(result);
                                
                                    if(file.open(QFile::ReadOnly) | QIODevice::Text)
                                    {
                                
                                        model->setHorizontalHeaderLabels(QStringList() << "Date/Time" << "PowerConsumed (W)");
                                
                                        int lineindex = 0;
                                        QTextStream flux(&file);
                                
                                
                                
                                        flux.readLineInto(nullptr); // Passe la 1ère ligne
                                
                                        QStringList lineList = {};
                                        QStringList columnList = {};
                                
                                
                                
                                        while(!flux.atEnd())
                                        {
                                            QString ligne = flux.readLine();
                                            QStringList champs = ligne.split(";", QString::KeepEmptyParts); //::KeepEmptyParts : Permet de voir les zones vides et de noter les résultats que quand il y en a
                                
                                            lineList.append(champs[0]);
                                            columnList.append(champs[1]);
                                            ui->customplot->graph(0)->setData(lineList, columnList);
                                            ui->customplot->replot();
                                
                                
                                            QString valueL = lineList[lineindex];
                                            QString valueC = columnList[lineindex];
                                            QStandardItem *itemL = new QStandardItem(valueL);
                                            QStandardItem *itemC = new QStandardItem(valueC);
                                            model->setItem(lineindex, 0,  itemL);
                                            model->setItem(lineindex, 1,  itemC);
                                
                                            lineindex++;
                                
                                        }
                                
                                        file.close();
                                
                                        ui->tableView->setModel(model);
                                
                                    }
                                
                                }
                                

                                I would like to display on my graph, the values of the two columns with x -> Date/Time and y -> PowerConsumed.

                                Here I have used the rows :

                                ui->customplot->graph(0)->QCPGraph::setData(lineList, columnList);
                                           ui->customplot->replot();
                                

                                I still don't know if this technique works but I get this as an error:
                                Can you help me please ?

                                C:\Users\46053500\Documents\Graph_QT\graphConso\graphconso.cpp:122: erreur : 'QCPGraph' is not a base of 'QCustomPlot'
                                             ui->customplot->QCPGraph::setData(lineList, columnList);
                                

                                I don't know what this means

                                JonBJ Online
                                JonBJ Online
                                JonB
                                wrote on last edited by
                                #18

                                @Raphawel
                                Your code shows

                                ui->customplot->graph(0)->QCPGraph::setData
                                

                                but the error message shows

                                ui->customplot->QCPGraph::setData
                                

                                so which do you actually have? Do you/are you supposed to have a QCPGraph object you are trying to call setData() on? I don't even know what your "if this technique works" refers to.

                                R 1 Reply Last reply
                                0
                                • JonBJ JonB

                                  @Raphawel
                                  Your code shows

                                  ui->customplot->graph(0)->QCPGraph::setData
                                  

                                  but the error message shows

                                  ui->customplot->QCPGraph::setData
                                  

                                  so which do you actually have? Do you/are you supposed to have a QCPGraph object you are trying to call setData() on? I don't even know what your "if this technique works" refers to.

                                  R Offline
                                  R Offline
                                  Raphawel
                                  wrote on last edited by
                                  #19

                                  @JonB Ohh sorry, the real mistake is this:

                                  With the line :

                                  lineList.append(champs[0]);
                                              columnList.append(champs[1]);
                                  
                                              //QVector<const char*> xData2 = lineList;
                                              //QVector<const char*> yData2 = columnList;
                                              ui->customplot->graph(0)->setData(lineList, columnList);
                                              ui->customplot->replot();
                                  

                                  And the error :

                                  C:\Users\46053500\Documents\Graph_QT\graphConso\graphconso.cpp:125: erreur : no matching function for call to 'QCPGraph::setData(QStringList&, QStringList&)'
                                               ui->customplot->graph(0)->setData(lineList, columnList);
                                                                                                     ^
                                  

                                  My IDE :
                                  6a93f9fc-ae33-4f74-a0f8-aa6b7ecc90da-image.png

                                  When I say if this technique works, I mean using:

                                  ui->customplot->graph(0)->setData(lineList, columnList);
                                  

                                  To display on the graph (custom plot object) the points from my csv file

                                  jsulmJ JonBJ 2 Replies Last reply
                                  0
                                  • R Raphawel

                                    @JonB Ohh sorry, the real mistake is this:

                                    With the line :

                                    lineList.append(champs[0]);
                                                columnList.append(champs[1]);
                                    
                                                //QVector<const char*> xData2 = lineList;
                                                //QVector<const char*> yData2 = columnList;
                                                ui->customplot->graph(0)->setData(lineList, columnList);
                                                ui->customplot->replot();
                                    

                                    And the error :

                                    C:\Users\46053500\Documents\Graph_QT\graphConso\graphconso.cpp:125: erreur : no matching function for call to 'QCPGraph::setData(QStringList&, QStringList&)'
                                                 ui->customplot->graph(0)->setData(lineList, columnList);
                                                                                                       ^
                                    

                                    My IDE :
                                    6a93f9fc-ae33-4f74-a0f8-aa6b7ecc90da-image.png

                                    When I say if this technique works, I mean using:

                                    ui->customplot->graph(0)->setData(lineList, columnList);
                                    

                                    To display on the graph (custom plot object) the points from my csv file

                                    jsulmJ Offline
                                    jsulmJ Offline
                                    jsulm
                                    Lifetime Qt Champion
                                    wrote on last edited by
                                    #20

                                    @Raphawel The error message is very clear.
                                    Please check documentation what parameters QCPGraph::setData expects (https://www.qcustomplot.com/documentation/classQCPGraph.html#a73578d786532132310a926c3cd529b29).

                                    https://forum.qt.io/topic/113070/qt-code-of-conduct

                                    R 1 Reply Last reply
                                    1
                                    • R Raphawel

                                      @JonB Ohh sorry, the real mistake is this:

                                      With the line :

                                      lineList.append(champs[0]);
                                                  columnList.append(champs[1]);
                                      
                                                  //QVector<const char*> xData2 = lineList;
                                                  //QVector<const char*> yData2 = columnList;
                                                  ui->customplot->graph(0)->setData(lineList, columnList);
                                                  ui->customplot->replot();
                                      

                                      And the error :

                                      C:\Users\46053500\Documents\Graph_QT\graphConso\graphconso.cpp:125: erreur : no matching function for call to 'QCPGraph::setData(QStringList&, QStringList&)'
                                                   ui->customplot->graph(0)->setData(lineList, columnList);
                                                                                                         ^
                                      

                                      My IDE :
                                      6a93f9fc-ae33-4f74-a0f8-aa6b7ecc90da-image.png

                                      When I say if this technique works, I mean using:

                                      ui->customplot->graph(0)->setData(lineList, columnList);
                                      

                                      To display on the graph (custom plot object) the points from my csv file

                                      JonBJ Online
                                      JonBJ Online
                                      JonB
                                      wrote on last edited by
                                      #21

                                      @Raphawel
                                      OK, so although you have not said I guess ui->customplot->graph(0) must be a QCPGraph?

                                      Given the error message tells you what the issue is I don't know what further to say. You are passing QCPGraph::setData() two QStringLists, list of strings, and not surprisingly it does not accept those. So look at QCPGraph::setData() documentation to see what it does accept.

                                      1 Reply Last reply
                                      0
                                      • jsulmJ jsulm

                                        @Raphawel The error message is very clear.
                                        Please check documentation what parameters QCPGraph::setData expects (https://www.qcustomplot.com/documentation/classQCPGraph.html#a73578d786532132310a926c3cd529b29).

                                        R Offline
                                        R Offline
                                        Raphawel
                                        wrote on last edited by
                                        #22

                                        @jsulm Yes the message tells me that I need QVectors inside setData() :

                                        void QCPGraph::setData ( const QVector< double > &  keys, const QVector< double > &  values, bool  alreadySorted = false  )
                                        

                                        So I readapted:

                                        lineList.append(champs[0]);
                                                    columnList.append(champs[1]);
                                        
                                                    QVector<double> xData2 = lineList;
                                                    QVector<double> yData2 = columnList;
                                                    ui->customplot->graph(0)->setData(xData2, yData2);
                                                    ui->customplot->replot();
                                        

                                        But I still have errors due to a conversion problem:

                                        C:\Users\46053500\Documents\Graph_QT\graphConso\graphconso.cpp:123: erreur : conversion from 'QStringList' to non-scalar type 'QVector<double>' requested
                                                     QVector<double> xData2 = lineList;
                                                                              ^
                                        
                                        C:\Users\46053500\Documents\Graph_QT\graphConso\graphconso.cpp:124: erreur : conversion from 'QStringList' to non-scalar type 'QVector<double>' requested
                                                     QVector<double> yData2 = columnList;
                                                                              ^
                                        

                                        I'm sorry if the errors are really glaring but I really don't see how to solve them

                                        S 1 Reply Last reply
                                        0
                                        • R Raphawel

                                          @jsulm Yes the message tells me that I need QVectors inside setData() :

                                          void QCPGraph::setData ( const QVector< double > &  keys, const QVector< double > &  values, bool  alreadySorted = false  )
                                          

                                          So I readapted:

                                          lineList.append(champs[0]);
                                                      columnList.append(champs[1]);
                                          
                                                      QVector<double> xData2 = lineList;
                                                      QVector<double> yData2 = columnList;
                                                      ui->customplot->graph(0)->setData(xData2, yData2);
                                                      ui->customplot->replot();
                                          

                                          But I still have errors due to a conversion problem:

                                          C:\Users\46053500\Documents\Graph_QT\graphConso\graphconso.cpp:123: erreur : conversion from 'QStringList' to non-scalar type 'QVector<double>' requested
                                                       QVector<double> xData2 = lineList;
                                                                                ^
                                          
                                          C:\Users\46053500\Documents\Graph_QT\graphConso\graphconso.cpp:124: erreur : conversion from 'QStringList' to non-scalar type 'QVector<double>' requested
                                                       QVector<double> yData2 = columnList;
                                                                                ^
                                          

                                          I'm sorry if the errors are really glaring but I really don't see how to solve them

                                          S Offline
                                          S Offline
                                          SimonSchroeder
                                          wrote on last edited by
                                          #23

                                          @Raphawel You need to transform all entries inside the lists individually. For example, you could use lineList[0].toDouble() to convert a single QString to a double value. There is not automatic conversion from strings to numbers. In imperative programming a for loop comes to mind. However, here is a more functional style approach to "copy" the data over using standard C++:

                                          QVector<double> xData2;
                                          std::transform(lineList.begin(), lineList.end(), std::back_inserter(xData2), [](const QString &str) { return str.toDouble(); });
                                          
                                          R 1 Reply Last reply
                                          1

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