CSV to QTaleWidget

Davide00

Hi, I am trying to read the csv file and showing the information through a dialog containing a QTableWidget, using this code:

QFile file("users.csv");

    QTextStream in(&file);
    QString loadCsv;

    int rowsCount = 1;

    while(!in.atEnd())
    {
        QString line = in.readLine();
        loadCsv = line.split("\t")[rowsCount - 1];
        int pos = loadCsv.lastIndexOf(',');
        loadCsv = loadCsv.left(pos);

        ui->tableWidget->setRowCount(rowsCount);
        ui->tableWidget->setColumnCount(loadCsv.size());

        for(int col = 0; col < loadCsv.size(); ++col)
        {
            QTableWidgetItem *items= new QTableWidgetItem(loadCsv.at(col));
            ui->tableWidget->setItem((rowsCount - 1), col, items);

        }

        rowsCount++;
    }

but it just shows me a blank table. What am I doing wrong?

JonB

@Davide00
Unless you put some qDebug() statements in there, we/you do not know how many rows or columns it is encountering or what visible string you are putting in any cells....

ui->tableWidget->setColumnCount(loadCsv.size());

If, for whatever reason, a blank line is encountered, say at the end, this would remove all previously-added columns from the table. Do you think this is safe coding?

mchinand

@Davide00 said in CSV to QTaleWidget:

    QString line = in.readLine();
    loadCsv = line.split("\t")[rowsCount - 1];
    int pos = loadCsv.lastIndexOf(',');
    loadCsv = loadCsv.left(pos);

This looks strange. You're parsing a single line here, I'm not sure why you are using rowsCount here. Is your data tab delimited or comma delimited? I would expect this to be just:

QString delimiter = ","; //specify the delimiter of your file
QStringList loadCsv = line.split(delimiter);

Davide00

@mchinand my data are delimited using "\t".
Actually this is a code i found on the internet, i tried to modify it because, ad the end of every row i used ",\n" to start a new line.
For example
"name1" << "\t" << "email1" << ",\n"
"name2" << "\t" << "email2" << ",\n" etc.
The problem is, it worked but it showed me ' , ' at the end of every row. I tried to modify the code in order to cancel the ' , ' but now it just show me a blank table.

mchinand

You could try:

auto loadCsv = line.split(",")[0].split("\t");

Edit: If it's your code that is creating the CSV file(s), I would fix that as well, so you don't need this.

Davide00

@JonB I've modified my code and used, now it looks like this:

void table_dialog::fill_table() {
    QFile file("utenti.csv");
    if(!file.open(QFile::ReadOnly | QFile::Text)) {
        return;
    }
    QTextStream in(&file);
    int cter = 0;

    while(in.atEnd()) {

        QString readedLine = in.readLine();
        QStringList listValue = readedLine.split(",");
        cter += 1;
        for(int i = 0; i < listValue.size(); ++i) {
            ui->tableWidget->setItem(cter-1, i, new QTableWidgetItem(listValue[i]));
        }
    }
    file.flush();
    file.close();
}

I used some qDebug too, and i noticed that readLine() and .split(",") are doing nothing (now i changed the delimeter from "\t" to ",").
What could possibly be the problem?

mchinand

@Davide00 said in CSV to QTaleWidget:

I used some qDebug too, and i noticed that readLine() and .split(",") are doing nothing (now i changed the delimeter from "\t" to ",").

Is your while loop not executed for each line in your file anymore? Are you setting the row and column count of your table anywhere? What do you mean readLine() and split() do nothing? What is the output of each? If you add qDebug() statements, include them in the code you paste here and what does the debugging output show. Also, can you also show us the first few rows of your csv file?

mpergand

@Davide00 said in CSV to QTaleWidget:

while(in.atEnd())

NOT atEnd() ;)

Davide00

@mchinand the code is the same as before, i just corrected the while condition into while(!in.atEnd())
I added a qDebug() like this

QString readedLine = in.readLine();
qDebug() << readedLine;
QStringList listValue = readedLine.split(",");
qDebug() << listValue

and i obtain the following:

20:24:10: Starting /home/LABORATORI/dc858025/login_form/login_form/login_form ...
"Wonder,Woman,3562145969,abcd,mer dic 25 1963,donna"
("Wonder", "Woman", "3562145969", "abcd", "mer dic 25 1963", "donna")
"Bruce,Wayne,imbatman@gmail.com,TheJoker27,mar mag 6 1975,uomo"
("Bruce", "Wayne", "imbatman@gmail.com", "TheJoker27", "mar mag 6 1975", "uomo")
20:24:24: /home/LABORATORI/dc858025/login_form/login_form/login_form exited with code 0

which is right considering that the csv file is exactly mae up of this two lines

Wonder | Woman | 3562145969         | abcd       | mer dic 25 1963  |  donna
Bruce  | Wayne | imbatman@gmail.com | TheJoker27 | mar mag 6 1975   |  uomo

the problem is that the QTableWidget is still empty, and i don't know why

Christian Ehrlicher

You don't set a row and column count so what do you expect?

Davide00

@Christian-Ehrlicher I've followed an half semester course on c++ and only the last three lessons were on Qt, so I basically know nothing.
How can i set a row and column?

mpergand

@Christian-Ehrlicher said in CSV to QTaleWidget:

You don't set a row and column count so what do you expect?

I've never used QTableWidget, but I thought rows and columns were created automatically as GridLayout do.
Disappointed i am :)

Christian Ehrlicher

@Davide00 said in CSV to QTaleWidget:

How can i set a row and column?

By clicking on my links and reading the documentation.

Davide00

So something like this

void table_dialog::fill_table() {
    QFile file("utenti.csv");
    if(!file.open(QFile::ReadOnly | QFile::Text)) {
        return;
    }
    QTextStream in(&file);
    int cter = 0;
    QString readedLine = in.readLine();
    QStringList listValue = readedLine.split(",");
    ui->tableWidget->setColumnCount(listValue().size());

    while(!in.atEnd()) {

        QString readedLine = in.readLine();
        QStringList listValue = readedLine.split(",");
        cter += 1;
        ui->tableWidget->setRowCount(cter);
        for(int i = 0; i < listValue.size(); ++i) {
            ui->tableWidget->setItem(cter-1, i, new QTableWidgetItem(listValue[i]));
        }
    }
    file.flush();
    file.close();
}

should do the work?

Davide00

@Davide00 However doing in this way, it only shows me the second row of elements

mchinand

You're reading the first line of your file in your three lines before the while loop. You could add a header to your csv file, so the header is read first and then all your data rows are read within the while loop. Alternatively, remove that readline() before the while loop and add this within loop:

if (listValue.size() > ui->tableWidget->columnCount()){
   ui->tableWidget->setColumnCount(listValue.size());
}

Davide00

@mchinand You've saved me, thank you very much