Remove string with greedy regular expression in QT

Question

thanks for any help in advance. I'm quite new to qt so please excuse my newbie question.

I want to replace image1="jdjddsj" with "im" with a regular expression in a string. There are more of these partes with xx="..." in my string, so I wanted to run QRegExp greedy, which somehow doesn't seem to work.

QString str_commando;

str_commando = "python python.py image1=\"sonstzweiteil\" one! path=\"sonstwas\" image2=\"sonsteinanderes\" two!"

QString str(str_commando); // The initial string.
qDebug() << str_commando.remove(QRegExp ("age1=\"([^>]*)\""));

/* Set field */
ui->lineeCommand->setText(str_commando);

Result is unfortunately: python python.py im two!

 qDebug() << str_commando.remove(QRegExp ("age1=\"([^>]*)\""));

I have tried it with before. Same result.

Where am I going wrong? Thanks for your help in advance!

SOLUTION:

qDebug() << str_commando.replace(QRegExp ("image1=\"([^\"]*)\""), "im");

Simply use "age1=\"([^>\"]*)\"". If you'd like a nongreedy pattern, you may try "age1=\"([^>]*?)\"" But I don't know if QT supports that. — Lucas Trzesniewski
– Lucas Trzesniewski, Commented Oct 8, 2015 at 19:36

JojOatXGME · Accepted Answer · 2015-10-08 19:41:48Z

2

The character set [^>] includes ". This mean the regex in

str_commando.remove(QRegExp ("age1=\"([^>]*)\""));

matches age1=\"sonstzweiteil\" one! path=\"sonstwas\" image2=\"sonsteinanderes\". If you are sure that there is no " between the quotes, you could set the regex minimal instead of greedy. Another solution would be to set the set [^>] to [^>"]. I also doesn't know why you are forbidding >.

After looking in the documentation of QString I think you could also do something like this:

str_commando.replace(QRegExp("image1=\"([^\"]|\\\")*\""), "im");

or if you want to have im="...":

str_commando.replace(QRegExp("image1=\"((?:[^\"]|\\\")*)\""), "im=\"\\1\"");

answered Oct 8, 2015 at 19:41

JojOatXGME

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1 Comment

madde Over a year ago

thanks a ton! you solved it for me! qDebug() << str_commando.replace(QRegExp ("image1=\"([^\"]*)\""), "im"); is what I'm using succesfully. I shouldn't just copy'n' paste regular expressions from old projects :)

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