QRegularExpression need help with patern

[AcerExtensa]

Hello all,

I just can't get it right.. maybe someone can help me with it?

I have QByteArray with list of elements in it and looks like that:

@
<!--story_23015_start--> test test 234 2tsdtsdf sf sdfds <!--story_23015_end-->
......
<!--story_2301275_start--> tsdtsdf sf sdfds <!--story_2301275_end-->
@

how can I extract numbers between "<!--story_" & "_start-->" and text in the midle from each item using QRegularExpression?

I will really appreciate your help!

[mcosta]

The following pattern works (RegExp Example)

@<!--story_(\d+)_start-->(.+)<!--story.+-->$@

[AcerExtensa]

Thank you very much mcosta

The problem is: items are not one per line and they can have text or any chars at the beginning or at the end. Like:
@
asdmpowq d34 23 <!--story_23015_start--> test test 234 2tsdtsdf sf sdfds <!--story_23015_end--> html tags etc
<!--story_2301275_start--> tsdtsdf sf sdfds <!--story_2301275_end-->
@

I have tried this way, but I just whole items as one item and not the list.

@
QRegExp rx("(.+)<!--story_(\d+)_start-->(.+)<!--story.+-->(.+)");
int pos = 0;
while((pos = rx.indexIn(data,pos)) != -1)
{
qDebug() << rx.cap(2) << pos;
pos += rx.matchedLength();
}
@

[mcosta]

Hi,

you could try to do this:

• remove all newline
• extract the signle tag
• applu the regular expression

[TheBadger]

Hi,

You can use an expression as follow:

@
<!--story_(\d+)start-->(.+)(?=<!--story(\d+)_end-->)
@

But I am not sure that the positive lookahead (?=) works on QRegExp, it should work according to the docs.

According to the docs the .(dot) should match newlines.

Hint: I normally use the following website to test my regular expressions, it works quite well: http://www.regexr.com/

[TheBadger]

Another interesting option is (sorry just escape for usage):

@
<!--story_(\d+)start-->([\s\S]+)<!--story(\1)_end-->
@

This can be used to make sure that the story number matches in the start and end using a "backreference":http://qt-project.org/doc/qt-4.8/qregexp.html#backreferences to the number captured in the start.

The [\s\S] is used if the .(dot) does not match a new line.

If you don't want to capture the number in the end tag you can use the (?:\1) tag to make a non-capturing group for that number.

Hope this helps a bit