Skip to content
  • Categories
  • Recent
  • Tags
  • Popular
  • Users
  • Groups
  • Search
  • Get Qt Extensions
  • Unsolved
Collapse
Brand Logo
  1. Home
  2. Qt Development
  3. General and Desktop
  4. Read data and add it to a chart
Forum Updated to NodeBB v4.3 + New Features

Read data and add it to a chart

Scheduled Pinned Locked Moved Unsolved General and Desktop
chartreal time plotplottingtimerfile read
28 Posts 5 Posters 5.9k Views 3 Watching
  • Oldest to Newest
  • Newest to Oldest
  • Most Votes
Reply
  • Reply as topic
Log in to reply
This topic has been deleted. Only users with topic management privileges can see it.
  • J jsulm
    4 Jan 2021, 08:52

    @suslucoder said in Read data and add it to a chart:

    I should use another struct instead of string list, right?

    You should use what the method to set the data expects. That's why I suggested to read the documentation: it is documented quite clearly.

    D Offline
    D Offline
    deleted286
    wrote on 4 Jan 2021, 09:17 last edited by
    #15

    @jsulm ıs there any example that doing exactly what you said?

    J 1 Reply Last reply 4 Jan 2021, 09:19
    0
    • D deleted286
      4 Jan 2021, 09:17

      @jsulm ıs there any example that doing exactly what you said?

      J Offline
      J Offline
      jsulm
      Lifetime Qt Champion
      wrote on 4 Jan 2021, 09:19 last edited by jsulm 1 Apr 2021, 09:21
      #16

      @suslucoder I already posted a link to charts examples.
      For example: https://doc.qt.io/qt-5/qtcharts-temperaturerecords-example.html
      And you still did not tell us what data you actually want to show and what type of chart you need...

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

      1 Reply Last reply
      1
      • M Offline
        M Offline
        mrjj
        Lifetime Qt Champion
        wrote on 4 Jan 2021, 09:52 last edited by
        #17

        Hi
        Please show one line from the "C:/Users/ilknu/Documents/QFileDemo/abc.txt"
        so we know how data is. else it's impossible to give any hints on how you can show that in a chart.

        D 1 Reply Last reply 4 Jan 2021, 10:39
        0
        • M mrjj
          4 Jan 2021, 09:52

          Hi
          Please show one line from the "C:/Users/ilknu/Documents/QFileDemo/abc.txt"
          so we know how data is. else it's impossible to give any hints on how you can show that in a chart.

          D Offline
          D Offline
          deleted286
          wrote on 4 Jan 2021, 10:39 last edited by
          #18

          @mrjj Here it is

          1991 01 213.5 136.9 0.64 220.5 147.6 229.4 205.5 8 17.4
          1991 02 270.2 167.5 0.62 221.5 147.6 243.0 206.3 10 18.4

          J 1 Reply Last reply 4 Jan 2021, 10:49
          0
          • D deleted286
            4 Jan 2021, 10:39

            @mrjj Here it is

            1991 01 213.5 136.9 0.64 220.5 147.6 229.4 205.5 8 17.4
            1991 02 270.2 167.5 0.62 221.5 147.6 243.0 206.3 10 18.4

            J Offline
            J Offline
            JonB
            wrote on 4 Jan 2021, 10:49 last edited by JonB 1 Apr 2021, 10:53
            #19

            @suslucoder

            QString line = read_one_line_from_file();
            QStringList list = line.split(QLatin1Char(' '), Qt::SkipEmptyParts);
            for (const QString &entry : list)
            {
                double num = entry.toDouble();    // or `unsigned num = entry.toUInt()` for the first 2 numbers on each line, by the look of it
                // do whatever is necessary with each `double` number retrieved
                // such as adding pairs directly to the chart, or building a `QLineSeries`, or whatever
            }
            
            D 1 Reply Last reply 4 Jan 2021, 11:03
            1
            • J JonB
              4 Jan 2021, 10:49

              @suslucoder

              QString line = read_one_line_from_file();
              QStringList list = line.split(QLatin1Char(' '), Qt::SkipEmptyParts);
              for (const QString &entry : list)
              {
                  double num = entry.toDouble();    // or `unsigned num = entry.toUInt()` for the first 2 numbers on each line, by the look of it
                  // do whatever is necessary with each `double` number retrieved
                  // such as adding pairs directly to the chart, or building a `QLineSeries`, or whatever
              }
              
              D Offline
              D Offline
              deleted286
              wrote on 4 Jan 2021, 11:03 last edited by
              #20

              @JonB Thank you. Where should I place the code script?

              J 1 Reply Last reply 4 Jan 2021, 12:10
              0
              • D deleted286
                4 Jan 2021, 11:03

                @JonB Thank you. Where should I place the code script?

                J Offline
                J Offline
                jsulm
                Lifetime Qt Champion
                wrote on 4 Jan 2021, 12:10 last edited by
                #21

                @suslucoder said in Read data and add it to a chart:

                Where should I place the code script?

                Come on. Place is where you read the data from the file...

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

                D 1 Reply Last reply 4 Jan 2021, 12:12
                0
                • J jsulm
                  4 Jan 2021, 12:10

                  @suslucoder said in Read data and add it to a chart:

                  Where should I place the code script?

                  Come on. Place is where you read the data from the file...

                  D Offline
                  D Offline
                  deleted286
                  wrote on 4 Jan 2021, 12:12 last edited by
                  #22

                  @jsulm I know but i have, QString line = in.readLine();
                  allLines.append(line);
                  I couldnt get the idea about it. When i do it i get out of index error .And after doing all this things, how can i add my datas to a chart?

                  D J 2 Replies Last reply 4 Jan 2021, 12:26
                  0
                  • D deleted286
                    4 Jan 2021, 12:12

                    @jsulm I know but i have, QString line = in.readLine();
                    allLines.append(line);
                    I couldnt get the idea about it. When i do it i get out of index error .And after doing all this things, how can i add my datas to a chart?

                    D Offline
                    D Offline
                    deleted286
                    wrote on 4 Jan 2021, 12:26 last edited by
                    #23

                    @suslucoder I did this part. After that, how can i add it to a chart? Like the way create a new chart, append series and it goes like this?

                    1 Reply Last reply
                    0
                    • D deleted286
                      4 Jan 2021, 12:12

                      @jsulm I know but i have, QString line = in.readLine();
                      allLines.append(line);
                      I couldnt get the idea about it. When i do it i get out of index error .And after doing all this things, how can i add my datas to a chart?

                      J Offline
                      J Offline
                      jsulm
                      Lifetime Qt Champion
                      wrote on 4 Jan 2021, 12:27 last edited by
                      #24

                      @suslucoder said in Read data and add it to a chart:

                      And after doing all this things, how can i add my datas to a chart?

                      I already provided links to examples several times.

                      "When i do it i get out of index error" - then post your code...

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

                      D 1 Reply Last reply 4 Jan 2021, 12:58
                      0
                      • J jsulm
                        4 Jan 2021, 12:27

                        @suslucoder said in Read data and add it to a chart:

                        And after doing all this things, how can i add my datas to a chart?

                        I already provided links to examples several times.

                        "When i do it i get out of index error" - then post your code...

                        D Offline
                        D Offline
                        deleted286
                        wrote on 4 Jan 2021, 12:58 last edited by
                        #25

                        @jsulm ```
                        QString line = in.readLine();
                        allLines.append(line);
                        QStringList list = line.split(QLatin1Char(' '), Qt::SkipEmptyParts);
                        for(const QString &entry : list) {
                        double num = entry.toDouble();
                        }
                        series->append(num)
                        ``
                        Says use of undeclared identifier num

                        1 Reply Last reply
                        0
                        • M Offline
                          M Offline
                          mrjj
                          Lifetime Qt Champion
                          wrote on 4 Jan 2021, 13:03 last edited by mrjj 1 Apr 2021, 20:00
                          #26

                          Hi
                          You want like

                          QStringList list = line.split(QLatin1Char(' '), Qt::SkipEmptyParts);
                          for(const QString &entry : list) {
                          double num = entry.toDouble();
                          series->append(X,Y);  // use num for either xor y or both depending on what you want
                          }
                          
                          S 1 Reply Last reply 4 Jan 2021, 19:55
                          1
                          • M mrjj
                            4 Jan 2021, 13:03

                            Hi
                            You want like

                            QStringList list = line.split(QLatin1Char(' '), Qt::SkipEmptyParts);
                            for(const QString &entry : list) {
                            double num = entry.toDouble();
                            series->append(X,Y);  // use num for either xor y or both depending on what you want
                            }
                            
                            S Offline
                            S Offline
                            SGaist
                            Lifetime Qt Champion
                            wrote on 4 Jan 2021, 19:55 last edited by
                            #27

                            @mrjj said in Read data and add it to a chart:

                            series->append(num); // add each number from the line

                            This cannot work as QLineSeries does not have such an overload.

                            Currently discussed here.

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

                            M 1 Reply Last reply 4 Jan 2021, 19:59
                            1
                            • S SGaist
                              4 Jan 2021, 19:55

                              @mrjj said in Read data and add it to a chart:

                              series->append(num); // add each number from the line

                              This cannot work as QLineSeries does not have such an overload.

                              Currently discussed here.

                              M Offline
                              M Offline
                              mrjj
                              Lifetime Qt Champion
                              wrote on 4 Jan 2021, 19:59 last edited by mrjj 1 Apr 2021, 20:00
                              #28

                              @SGaist
                              Good catch.
                              yes its x,y.
                              It was more about num being undeclared at that point in time :)
                              Changed as not to confuse future readers.

                              1 Reply Last reply
                              0

                              24/28

                              4 Jan 2021, 12:27

                              • Login

                              • Login or register to search.
                              24 out of 28
                              • First post
                                24/28
                                Last post
                              0
                              • Categories
                              • Recent
                              • Tags
                              • Popular
                              • Users
                              • Groups
                              • Search
                              • Get Qt Extensions
                              • Unsolved