Called on an invalid QRegularExpression object warning

[samzhcs1]

QRegularExpression re2("^=?[a-z1-9A-Z\s+-*/]*");
QRegularExpressionMatch mat = re2.match(tst);

The above code generated called on an invalid QRegularExpression object warning, while the following code works well.
QRegularExpression re3("\\");
QRegularExpressionMatch mat = re3.match(tst);

But I tried with :
QString pattern("^=?[a-z1-9A-Z\s+-*/]*");
QRegExp rx(pattern);
bool match = rx.exactMatch(tst);
then it works well.

Anybody know the reason?

Thanks

[SGaist]

Hi,

Your first star is the problem.

What exactly are you trying to search ?

[samzhcs1]

should be this expression, don't know why when I posted it, browser seems removed some backslashes

[SGaist]

Still your first * is the problem. Hence my question, what do you want to extract exactly with your expression ?

[samzhcs1]

I want to match the following string:
Number, 1 2 3 ..
and A1 b3 C3 ..M19 ..
formula: =A1+B1 / c3 ...

[samzhcs1]

@SGaist then how can I put a Arithmetic operator * in the expression?

[SGaist]

^=?[a-z1-9A-Z\s*/+-]*

You can use the regular expression tool from Qt's example to test your regular expressions with Qt.

[samzhcs1]

It's the \ escaped character reason.