How to get the regular expression matched part

Mihan

Hi
I want to get the address like IP from a string.
e.g. Device address: 192.168.1.1
Local address: 192.168.1.2

I have gotten a regular expression QRegExp("(\\d{1,3}\\.){3}\\d{1,3}") to match address.
So how to use this regular expression to get the address, not use it to spilt.

Regards
Mihan

Christian Ehrlicher

See QRegularExpression::match()

Mihan

@Christian-Ehrlicher Thanks, QRegularExpression is something I haven't known.

What's the different of QRegExp and QRegularExpression

Bonnie

@Mihan You can also get the address by QRegExp.

QString device="Device address: 192.168.1.1";
QRegExp rx("(\\d{1,3}\\.){3}\\d{1,3}");
if(rx.indexIn(device) >= 0) {
    qDebug() << rx.cap();
}

As the doc says

Note: In Qt 5, the new QRegularExpression class provides a Perl compatible implementation of regular expressions and is recommended in place of QRegExp.

You can check this page for the difference of the two classes:
https://doc.qt.io/qt-5/qregularexpression.html#notes-for-qregexp-users

JonB

@Mihan
There's a reference somewhere which could be dug out if you want (edit Oh I see @Bonnie has provided one), but in a nutshell QRegExp has been superseded by QRegularExpression and you should use the latter now.

Mihan

@JonB @Bonnie
Thank you so much.

Now I have replaced all the QRegExp with QRegularExpression.

Best regards
Mihan

KroMignon

@Mihan said in How to get the regular expression matched part:

Now I have replaced all the QRegExp with QRegularExpression.

By the way QRegExp has been deprecated by Qt => QTBUG-72974