@HeerokNewbie said in How to parse firebase GetUserData request's response?: Please correct this code 🙏 Too lazy to learn by yourself? "users" is an Array.

Thanks for the reply @SGaist. What I wanted was to update some data (in form of text) from python backend, most of the tutorials I saw were based on using signals and slots. were as I only needed a slot to read without any triggering signal. Though I've been able to finally figure it out and spending this much time actually made me understood it more. I used QTimer to refresh the backend function every half a second.

@Sina-Ranjkesh-zade said in Converting QByteArray to QString: For "standard input" if you mean input arguments of the process, I got this error: No, I meant standard input. That is , the python program reads from a terminal and accepts input just as if you typed it (except it is the Qt program sending that input). The Qt program can send a command to the python program, send the data it needs, and read the result (if there is one) back on the python program's standard output. Or you can used shared memory, or a socket, or files, or do whatever the python program is doing in the Qt program...

@JKSH Oh wow, you're completely right. I didn't know qDebug() behaved like this, I assumed noquote() was the default. Thanks for the help, I don't know how long it would have taken me to find out.

@JKSH I'll leave that here...

@JonB thanks!

Hi, One possible way is to use QRegularExpression::match or since it looks like xml, you can use QXmlStreamReader.

@JonB tests are in order ! It would indeed be simpler. As I miswrote (and fixed) it's possibly a memory issu :-).

Now I realized I have to set QDataStream::setVersion to QDataStream::Qt_4_7. I think the problem is solved.

Thanks for your replies. It probably doesn't matter at all, because the only result will be that the library is a few micro seconds faster at runtime / at load time. The reason is probably rather a psychological one than a real performance issue. -- I'd like to write clean code, use the ideal way and don't want to see warnings when running i.e. clazy on my code. When looking at performance there are probably other issues that have a greater impact on the performance. I actually tested it now: Test 1: Runtime usage #include <QString> const char *xmlns = "urn:ietf:xml:ns:xmpp-sasl"; // OR: const QString xmlns = QStringLiteral("urn:ietf:xml:ns:xmpp-sasl"); int main() { for (int i = 0; i < 1e9; i++) { // Option A: QString text(xmlns); // Option B: appending 'a' QString xmlnsPlusA = QString(xmlns) + 'a'; } } QStringLiteral char* A: QString( ), QStringLiteral is implicitly-shared 0.5 s 52 s B: appending 'a' 27 s 91 s -> The relative difference is high, but the absolute numbers are not relevant: You need to convert about 500 kB (about 20k comparable strings), so that this takes more than 1 ms and gets a performance problem in a GUI application. Test 2: Start-up time I also created a test binary with 10k global static constants (all with the same content): QString (cast from char *) QStringLiteral char * compile time 3 s 3.5 min < 1 s binary size (stripped) 410 kB 1270 kB 320 kB time to run (10k times) 33 s 23 s 19 s I guess the QStringLiteral binary takes longer to run, because it is larger and only partially, because of the non-POD CTORs. -> Using QStringLiteral has a slightly larger impact on the execution time than I've expected, but this is still not relevant since you usually have less than 10k global static strings and you only load the binary once instead of 10000 times. As long as you're not developing for an arduino this has probably no relevance. As expected the usage of QStringLiteral makes the binary a bit larger, the start-up time a little little bit larger, but is faster compared to casting from ascii everytime at runtime. I'll see if I can do anything with QArrayData, not because it's important, just for fun.

@emp1953 said in How to remove quotes and eol characters from QString?: There is still the annoying little "square" shape after every item in the QListWidget. QFile::readLine() behaves different on Windows and Linux, your can read that in the docu. On Linux it assumes \n line endings, on Windows \r\n ones, which it replaces with \n. Your file is none of these, it has mixed endings. If you want to use it in Linux, you have to normalize the line endings first. Otherwise readLine() will not do what you expect and every following procedure will fail. The square bracket you see is probably the \r char, which cannot be displayed otherwise. From within the Qt Creator development environment it does in fact compile without warnings and outputs an executable. But not the code you posted above. This code is invalid and no compiler will accept it. Double check what you are doing. Regards

@JKSH said in How do I append characters of a QString to another QString in a neat way?: Anyway, you could simplify the whole thing: QDateTime now = QDateTime::currentDateTime(); QString yyyy = now.toString("yyyy"); QString MM = now.toString("MM"); QString dd = now.toString("dd"); QString HH = now.toString("HH"); QString mm = now.toString("mm"); QString ss = now.toString("ss"); This is ideally the best general solution, IMHO

@VRonin said in Number of characters that fit into given width: Something like http://doc.qt.io/qt-5/qfontmetrics.html#elidedText ? Turns out it will not work for me. The QString returned includes the ellipsis and there is no way to avoid them, because passing Qt::ElideNone means "do not truncate" instead of "omit the ellipsis" (as I feared).

Here are a couple of variations that worked for me in Visual Studio 2017: diac = QStringLiteral("ÀÉ"); uint chin[] = {0x4E83, 0}; // L'亃' diac2 = QString::fromUcs4(chin); wchar_t chinW[] = {L'亃', 0}; wchar_t *chinW2 = L"亃"; diac3 = QString::fromWCharArray(chinW2); // also chinW diac += diac2 + diac3; Sorry I just realized you want to go the other way.

@Kushan Simple C++: class Dialog2 : public QDialog { Q_OBJECT private slots: void receiveValue2 (QString val) public: QString Value explicit Dialog2(QWidget *parent = 0); ~Dialog2(); void setValue(const QString &val) { Value=val; } private: Ui::Dialog2 *ui; }; ... void MainWindow::on_pushButton_clicked() { value=ui->line_Edit->text(); Dialog dialog1; dialog1.setValue(value); }

Hi Normally its the that can give "index out of range error" not when inserting ?

@SGaist Dman that was silly mistake :(

While I'm here, you can use https://github.com/VSRonin/Qt-Model-Serialisation/tree/dev CsvModelSerialiser modelSaver; modelSaver->setModel(ui->tableWidget_2->model()); modelSaver->setCsvSeparator(" "); QFile mFile("C:/Users/Desktop/Qt/textfiles/test.txt"); modelSaver->saveModel(&mFile);

Hi ... oh yes i read line by line.. each line have other language to detect.. wich so much text in over 200 or more language... google the file name test_shuffle_1000_48_666.utf8.gz i tested for https://github.com/pehohlva/QCLD2 for language detection .. the error was unclosed array cycle that fill ram... not QString... have incremented all line... :-) & must go in assert -

One small note, you are wasting CPU cycle here. The QRegularExpressionMatchIterator returns only match objects that contains a match thus the if is useless.

Then use "<br>" instead of "\n"

ah thanks - using \\1 instead of $1 works as i want it. And thanks for the other solution with the For-Loop.

Sure, they are in the docs: http://doc.qt.io/qt-5/qregexp.html#code-examples indexIn() method should interest you in this case.

The reason for this is a GDB limitation on Windows. See QTCREATORBUG-24649 for more information. Regards

@Rohith instead of converting the unicode string to the escaped characters send it directly in binary form. When you have a QString already you can call QString::toUtf8() and send the returned QByteArray directly. On the client its enough to do QString::fromUtf8( receivedUtf8ByteArray.constData() ) It depends how you implemented the transfer. But theoretically it should be enough to replace your unicode escaping code on the server with this approach.

Thanks !! I just figured it out after reading Docs !! Thanks for replying (y)

@micland WOOW!!! Thank you sooo much micland!! It works!!! I tried a code similar to yours but some data were missing. Just needed to do a very tiny modification on your code: qDebug() << key << value.variant().toString(); or directly qDebug() << value.variant().toString(); Except it, it is perfect! Thank you again. @micland said: I have no clue why the qdbusviewer of Qt 5.6 is unable to call the DBus method but the code snippet above is working fine. I hope it is going to change as I intend to use it or the 5.7 version very soon. Cheers again.

@Mandar-Khire If you change your basic C++ program like this then you will not see the output as well: #include <iostream> using namespace std; int main() { cout << "Hello World by C++!"; while(true); return 0; } Qt uses an event loop, so after executing void Widget::on_showButton_clicked() { cout << "Hello World by QT!"; } your program is "sleeping" in the event loop and not flashing cout buffer.

Hi @Wieland , I did not test the code. But Yes, you are right. I tested @Punit 's code after my comment. It worked for me too(missed only that semicolon).

If .toAscii() worked for you before, you can savely use .toLatin1(), too, and ^Z will be preserved.

Thank you a lot for quick and exact answer!

@Paul-Colby thank you

The assertion is expected behaviour for QString::at The position must be a valid index position in the string (i.e., 0 <= position < size()). Instead, you should do something like: if (5 >= a.size()) { out << "Outside the range of the string" << endl; } Cheers.

@the_ @SGaist Hi, I managed to solve it on my own by encoding the date to a JulianDate and using juliandate on my db so it's much easier to compare and so. Thanks for your help.

@mrjj Thanks Mrjj :) it went perfect, you're awesome haha ;)

@kshegunov Thank you so much for the help! Such a simple mistake

@mrjj that is right :D

I solved my problem with not calling parseFunction in its own class constructor but with signals and slots in mainwindow.cpp file: connect(xml, SIGNAL(started()), first, SLOT(parseFunction()));