QRegExp floating point matching

kybernetes

i want to use foating points in a line and i tried to do that

        if(line.contains("lineto"))
        {
            QRegExp rxValues("\\d+\\.\\d+");    // primitive floating point matching
            rxValues.indexIn(line);

            out << "obj.lineTo(" + rxValues.cap(1) +  ", " + rxValues.cap(2) << "\n";

            qDebug() << rxValues.cap(1);
            qDebug() << line;
        }

debug is like that

""
"512.00 512.00 lineto"
""
"512.00 0.00 lineto"
""
"0.00 0.00 lineto"
""
"0.00 512.00 lineto"

why it doest work? why rxValues.cap(1) is empty?

SGaist

Hi,

Because you're not capturing anything with that regexp. It should be "(\\d+)\\.(\\d+)"

On a side note, if you are using Qt 5, consider moving to QRegularExpression.

kybernetes

thanks for your fast reply.

i tried your suggestion and it works like that

qDebug() << rxValues.cap(1);
qDebug() << rxValues.cap(2);
qDebug() << line;

"512"
"00"
"512.00 511.00 lineto"

but i want the number "512.00" and "511.00"

as u see cap(1) = 512 and cap(2) = 00

and i was waiting cap(3) = 511 but i was "" nothing.

jsulm

QRegularExpression reg("(\\d+\\.\\d+)");
qDebug() << reg.match("512.00 512.00 lineto");

SGaist

Sorry, I misunderstood your original problem, @jsulm suggestion is the best way to go.

kybernetes

       Thanks for your answers.

i used QRegularExpression and write my code like below. i think captured(1) is second number for me but debug is like that captured(0) and captured(1) is same but i didnt why.

i think;
captured(0) has to be 512.00 and captured(1) has to be 0.00

            QString line = "512.00 0.00 lineto";
            QRegularExpression rxValues("(\\d+\\.\\d+)");
            QRegularExpressionMatch match = rxValues.match(line);

            qDebug()<< match.captured(0);
            qDebug()<< match.captured(1);
            qDebug()<< line;

debug output

"512.00"
"512.00"
"512.00 0.00 lineto"

jsulm

QRegularExpressionMatchIterator iter = reg.globalMatch("512.00 2.00 lineto");
while (iter.hasNext()) {
    qDebug() << iter.next().captured();
}