How to make qt regex avoid matching already captured values?

[Kattia]

I have a very big log file that contains some lines in this format:

2024-04-14 04:56:56.714-0300 24180 20660 UI  at64_1 [Ready] W: Retrying to obtain clipboard.
2024-04-14 04:56:56.714-0300 27268 31992 UI  at64_4 [Ready] W: Retrying to obtain clipboard.
2024-04-14 04:56:56.714-0300 3696  20128 UI  at64_3 [Ready] W: Retrying to obtain clipboard.
2024-04-14 04:56:56.765-0300 3696  20128 UI  at64_3 [Ready] W: Retrying to obtain clipboard.
2024-04-14 04:56:56.765-0300 27268 31992 UI  at64_4 [Ready] W: Retrying to obtain clipboard.
2024-04-14 04:56:56.765-0300 17532 1384  UI  at64_2 [Ready] W: Retrying to obtain clipboard.

These lines always start in the format 2024-04-14 04:56:56.714-0300, but with different timestamps.

I know only the numbers after -0300 : 24180, 27268, 3696, 17532, etc
and I'm trying to get the at64_... strings relative to the number line.

From the example above i would like to get:

24180, at64_1

27268, 64_4

3696, 64_3

17532, 64_2

I have written this regex: (24180|27268|3696|17532)(?!.*\1)\s+\d+\s+\w+\s+\K\w+

I have used (?!.*\1) to avoid capturing duplicated values, but using the same regex on Qt QRegularExpression, it's capturing duplicated values:

int main(int argc, char* argv[])
{
    QCoreApplication a(argc, argv);

    QString content = R"(2024-04-14 04:56:56.714-0300 24180 20660 UI  at64_1 [Ready] W: Retrying to obtain clipboard.
2024-04-14 04:56:56.714-0300 27268 31992 UI  at64_4 [Ready] W: Retrying to obtain clipboard.
2024-04-14 04:56:56.714-0300 3696  20128 UI  at64_3 [Ready] W: Retrying to obtain clipboard.
2024-04-14 04:56:56.765-0300 3696  20128 UI  at64_3 [Ready] W: Retrying to obtain clipboard.
2024-04-14 04:56:56.765-0300 27268 31992 UI  at64_4 [Ready] W: Retrying to obtain clipboard.
2024-04-14 04:56:56.765-0300 17532 1384  UI  at64_2 [Ready] W: Retrying to obtain clipboard.)";

    QRegularExpression re(R"((24180|27268|3696|17532)(?!.*\1)\s+\d+\s+\w+\s+\K\w+)");
    QRegularExpressionMatchIterator match = re.globalMatch(content);
    if (!match.hasNext())
        qDebug() << "failed";
    
    while (match.hasNext())
    {
    	QRegularExpressionMatch nextMatch = match.next();
    	qDebug() << nextMatch.captured(1) << "|" << nextMatch.captured(0);
    }
}

This code prints:

"24180" | "at64_1"
"27268" | "at64_4"
"3696"  | "at64_3"
"3696"  | "at64_3"
"27268" | "at64_4"
"17532" | "at64_2"

It has captured duplicated values, different from the result seen here: https://regex101.com/r/IFJ1Oy/2

I'm using Qt 6, is it possible to make the QRegularExpression avoid capturing duplicates or will I necessarily need to parse it and remove the duplicates myself?

[Christian Ehrlicher]

@Kattia You have to do it by yourself.

btw: Why using regex here at all? Simply split the string by and use index-based lookup - much better to read and understand what's going on.

[Tassos]

@Kattia I think passing these options to re will give you the desired results :)

  QRegularExpression re(R"((24180|27268|3696|17532)(?!.*\1)\s+\d+\s+\w+\s+\K\w+)", QRegularExpression::DotMatchesEverythingOption|QRegularExpression::MultilineOption);