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  4. Getting a specific text from a text file and inserting to a QStringList!

Getting a specific text from a text file and inserting to a QStringList!

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qt creatortextfilereadvalue
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  • L Offline
    L Offline
    Lasith
    wrote on last edited by Lasith
    #1

    IN my qt c++ application I have created a functionality to upload and read text files! I want to get a specific part of selected text lines to a QStringLIst!
    Following is my code

    MainWindow.h

    #ifndef MAINWINDOW_H
    #define MAINWINDOW_H
    
    #include <QMainWindow>
    
    namespace Ui {
    class MainWindow;
    }
    
    class MainWindow : public QMainWindow
    {
        Q_OBJECT
    
    public:
        QString filepath;
        void readValues();
        QStringList values;
        explicit MainWindow(QWidget *parent = 0);
        ~MainWindow();
    
    private slots:
        void on_pushButton_clicked();
    
        void on_pushButton_2_clicked();
    
    private:
        Ui::MainWindow *ui;
    };
    

    MainWindow.cpp

    #include "mainwindow.h"
    #include "ui_mainwindow.h"
    #include "QFileDialog"
    #include "QTextStream"
    
    MainWindow::MainWindow(QWidget *parent) :
        QMainWindow(parent),
        ui(new Ui::MainWindow)
    {
        ui->setupUi(this);
    }
    
    MainWindow::~MainWindow()
    {
        delete ui;
    }
    
    void MainWindow::on_pushButton_clicked()
    {
        filepath=QFileDialog::getOpenFileName(this, "Get Any File");
            ui->lineEdit->setText(filepath);
    }
    
    void MainWindow::readValues(){
        QFile file(filepath);
           if (!file.open(QIODevice::ReadOnly | QIODevice::Text))
               return;
    
        QTextStream in(&file);
              while (!in.atEnd()) {
    
                  QString line = in.readLine();
               
                  values<<line;
                  }
           }
              ui->label->setText(QString::number(values.size()));
    }
    
    void MainWindow::on_pushButton_2_clicked()
    {
        readValues();
    }
    

    The text file(names.txt) I read have the following format!

    <h>Hello<h>
    <name>John</name>
    <h>Hello<h>
    <name>Smith</name>
    <h>Hello<h>
    <name>Mary</name>
    <h>Hello<h>
    <name>Anne</name>
    <h>Hello<h>
    <name>Jennifer</name>
    <h>Hello<h>

    Currenly I get all the text lines into the QStringList!
    I want to get the words(without <name></name> tags) John,Smith,Marry,Anne,Jennifer into the QStringList named values! How can I do it?

    1 Reply Last reply
    0
    • VRoninV Offline
      VRoninV Offline
      VRonin
      wrote on last edited by VRonin
      #2
      void MainWindow::readValues(){
      QFile file(filepath);
      if (!file.open(QIODevice::ReadOnly | QIODevice::Text))
      return;
      const QRegularExpression nameExp(R"***(<name>(.+)<\/name>)***");
      QTextStream in(&file);
      QString line;
      while (stream.readLineInto(&line)) {
      const auto nameMatch = nameExp.match(line);
      if(nameMatch.hasMatch())
      values << nameMatch.captured(1);
      }
       ui->label->setText(QString::number(values.size()));
      }
      

      "La mort n'est rien, mais vivre vaincu et sans gloire, c'est mourir tous les jours"
      ~Napoleon Bonaparte

      On a crusade to banish setIndexWidget() from the holy land of Qt

      L 1 Reply Last reply
      4
      • VRoninV VRonin
        void MainWindow::readValues(){
        QFile file(filepath);
        if (!file.open(QIODevice::ReadOnly | QIODevice::Text))
        return;
        const QRegularExpression nameExp(R"***(<name>(.+)<\/name>)***");
        QTextStream in(&file);
        QString line;
        while (stream.readLineInto(&line)) {
        const auto nameMatch = nameExp.match(line);
        if(nameMatch.hasMatch())
        values << nameMatch.captured(1);
        }
         ui->label->setText(QString::number(values.size()));
        }
        
        L Offline
        L Offline
        Lasith
        wrote on last edited by
        #3

        @VRonin Thanx I get an errors stating
        "R was not declared in this scope"
        "stream was not declared in this scope"
        "nameMatch does not name a type"
        "nameMatch was not declared in this scope"

        VRoninV 1 Reply Last reply
        0
        • L Lasith

          @VRonin Thanx I get an errors stating
          "R was not declared in this scope"
          "stream was not declared in this scope"
          "nameMatch does not name a type"
          "nameMatch was not declared in this scope"

          VRoninV Offline
          VRoninV Offline
          VRonin
          wrote on last edited by VRonin
          #4

          "R was not declared in this scope"

          Old compiler? that's C++11. use const QRegularExpression nameExp("<name>(.+)<\\/name>"); then

          "stream was not declared in this scope"

          change while (stream.readLineInto(&line)) into while (in.readLineInto(&line))

          "nameMatch does not name a type"

          again old compiler const QRegularExpressionMatch nameMatch = nameExp.match(line);

          "nameMatch was not declared in this scope"

          The above solves this too

          "La mort n'est rien, mais vivre vaincu et sans gloire, c'est mourir tous les jours"
          ~Napoleon Bonaparte

          On a crusade to banish setIndexWidget() from the holy land of Qt

          L 1 Reply Last reply
          2
          • VRoninV VRonin

            "R was not declared in this scope"

            Old compiler? that's C++11. use const QRegularExpression nameExp("<name>(.+)<\\/name>"); then

            "stream was not declared in this scope"

            change while (stream.readLineInto(&line)) into while (in.readLineInto(&line))

            "nameMatch does not name a type"

            again old compiler const QRegularExpressionMatch nameMatch = nameExp.match(line);

            "nameMatch was not declared in this scope"

            The above solves this too

            L Offline
            L Offline
            Lasith
            wrote on last edited by
            #5

            @VRonin Thanx if there are several blank spaces before "<name>" how do I need to change the code?

            VRoninV 1 Reply Last reply
            0
            • L Lasith

              @VRonin Thanx if there are several blank spaces before "<name>" how do I need to change the code?

              VRoninV Offline
              VRoninV Offline
              VRonin
              wrote on last edited by
              #6

              add \\s* wherever there could be empty space

              "La mort n'est rien, mais vivre vaincu et sans gloire, c'est mourir tous les jours"
              ~Napoleon Bonaparte

              On a crusade to banish setIndexWidget() from the holy land of Qt

              L 1 Reply Last reply
              2
              • VRoninV VRonin

                add \\s* wherever there could be empty space

                L Offline
                L Offline
                Lasith
                wrote on last edited by
                #7

                @VRonin unfortunately there is another error stating "class QTextStream has no memebr named readLineInto"

                1 Reply Last reply
                0
                • VRoninV Offline
                  VRoninV Offline
                  VRonin
                  wrote on last edited by
                  #8

                  What version of Qt are you using?

                  Replace it with your

                   while (!in.atEnd()) {
                  line = in.readLine();
                  

                  "La mort n'est rien, mais vivre vaincu et sans gloire, c'est mourir tous les jours"
                  ~Napoleon Bonaparte

                  On a crusade to banish setIndexWidget() from the holy land of Qt

                  L 1 Reply Last reply
                  3
                  • VRoninV VRonin

                    What version of Qt are you using?

                    Replace it with your

                     while (!in.atEnd()) {
                    line = in.readLine();
                    
                    L Offline
                    L Offline
                    Lasith
                    wrote on last edited by
                    #9

                    @VRonin Thanx alot! I use Qt 5.2

                    JKSHJ 1 Reply Last reply
                    0
                    • L Lasith

                      @VRonin Thanx alot! I use Qt 5.2

                      JKSHJ Offline
                      JKSHJ Offline
                      JKSH
                      Moderators
                      wrote on last edited by JKSH
                      #10

                      @Lasith said in Getting a specific text from a text file and inserting to a QStringList!:

                      I use Qt 5.2

                      That's not supported anymore.

                      Is it feasible for you to upgrade to a newer version? (Qt 5.10.0 was released last week)

                      Qt Doc Search for browsers: forum.qt.io/topic/35616/web-browser-extension-for-improved-doc-searches

                      1 Reply Last reply
                      2

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