How to split QString using QRegex?

npatil15

Hello,

I want to split this: {($..Properties[*])-($..Layer_Index)}
Like: ("$..Properties[*]", "$..Layer_Index")

I have tried some examples and online regex tester, I'm getting output but it's not working here.

On this link: Regex Online Tester
I have tried with $.*?$
But in code, it's not working.

I have tried with many expressions but not working

What I'm missing?

npatil15

I got my mistake,

instead of using re.match(query), I have to used re.globalMatch(query) to get all matched information.

Thanks for all of yours efforts.

Christian Ehrlicher

@npatil15 said in How to split QString using QRegex?:

But in code, it's not working.

First please use QRegularExpression, second please show us the code. Be aware that you have to escape '\'.

npatil15

I have tried the below method.

For reference, I have used below code

    QString query("{($..Properties[*])-($..Layer_Index)}");
    QStringList list = query.split(QRegularExpression("\\(.*?\\)"));
    qDebug()<<"Output: "<<list;

//Output --> Output:  ("{", "-", "}")

And I have checked on many online regex testers like this one https://regexr.com/
And output is like bold marked: {($..Properties[*])-($..Layer_Index)}

So why there is so differences in this outputs.

KroMignon

@npatil15 Hmm, I think you should do it like this:

QStringList list = query.split(QRegularExpression("({\\(|\\)-\\(|\\)})"), QString::SkipEmptyParts);

npatil15

@KroMignon said in How to split QString using QRegex?:

@npatil15 Hmm, I think you should do it like this:
QStringList list = query.split(QRegularExpression("({\$|\$-\$|\$})"), QString::SkipEmptyParts);

Thanks a lot, it works like charm. :)

SGaist

Hi,

Out of curiosity, are you needing to split ? Otherwise, you could also use QRegularExpession::match and extract each side from the returned QRegularExpressionMatch object. It might look a bit more complicated but you will also be more precise in what you are extracting.

npatil15

@SGaist ,

Yes I'm about to drop reply.

The solution mentioned by @KroMignon , it works if I have specific expressions, but I may have multiple expressions like: {($..Properties[*])-($..Layer_Index)+($..Name==Value())/($..Properties(Name==True))}

So here in the above expression, I want to split text like:

$..Properties[*]
$..Layer_Index
$..Name==Value()
$..Properties(Name==True)

And more over want to split the math symbol like, -,+,/. To do the mathematical operations.

I have tried with your suggestions as mentioned in below code:

    QString query("{($..Properties[*])-($..Layer_Index)+($..Name==Value())/($..Properties(Name==True))}");
    QRegularExpression re;
    re.setPattern("\\(.*?\\)");
    QRegularExpressionMatch match = re.match(query);
    qDebug()<<"Match 0: "<<match.captured(0);
    qDebug()<<"Match 1: "<<match.captured(1);
    qDebug()<<"Match 2: "<<match.captured(2);

Output:
Match 0:  "($..Properties[*])"
Match 1:  ""
Match 2:  ""

I think I'm passing incorrect pattern, which I didnt understanding, how to split all between the ( ) brackets but not the brackets inside bracket like Name==True from ($..Properties(Name==True)).
What I'm missing here to get a list of all split strings?

SGaist

Do you have some sort of DSL ?

npatil15

I got my mistake,

instead of using re.match(query), I have to used re.globalMatch(query) to get all matched information.

Thanks for all of yours efforts.