How to avoid reading "\n" when using QFile::readAll function

Question

I have a "sequence.dat" file that contains "1"s and "-1"s in a vertical representation (i.e.: each element is in a single line).. I am trying to read the file as follow:

QFile sequence("Sequences.dat");
sequence.open(QIODevice::ReadOnly);
QByteArray data = sequence.readAll(); 
for(int i=0; i<29; i++){        
    signedNo[i] = data[i]; // debugging breaking point
}
sequence.close();

however, at the debugging breaking point, the QByteArray "data" contains "1, -, 1, \n" instead of "1,-1" ...

is there is away to read the whole line at once and not each byte individually ? and ... if there is not, how to tell the "readAll" function to avoid the "\n" (it is not an optimal solution because I want also to read "-1" and not "- and 1" separately)

Answer 1

QFile::readAll() returns a byte array which contains each and every byte of the file as a separate element.

For your use case, you need to read the file line by line.

The QFile documentation shows some approaches how to do this, for example:

 QVector<int> elements;

 QFile sequence("Sequences.dat");
 if (!sequence.open(QIODevice::ReadOnly | QIODevice::Text))
     return;

 QTextStream in(&sequence);
 while (!in.atEnd()) {
     QString line = in.readLine();
     elements.append(line.toInt());
 }

Despite the fact that this sample is from the Qt documentation, I would recommend to check the return value from in.readLine() which returns a null QString when the end of the file has been reached, instead of using atEnd().

Answer 2

You could read line by line, and you could process it right after you read the line:

 i = 0;
 while (!sequence.atEnd()) {
     QByteArray line = sequence.readLine();
     signedNo[i] = line[i];
     i++;
 }