Not getting what I expected using a regex in QRegExpValidator.

ealione

I am using a QLineEdit with a QRegExpValidator in order to limit inputs to this type:

a.green or d.yellow4 and so on.

So basically one lowercase character followed by a period and then an arbitrary number of characters and possibly a number at the end.

What I have are the following

QRegExp textValidator("^[a-z]+\.?[a-z]+[0-9]*$"); 
QRegExpValidator *validator = new QRegExpValidator(textValidator, 0);

and

QRegExp textValidator("[a-z]\.\w++"); 
QRegExpValidator *validator = new QRegExpValidator(textValidator, 0);

With the first one allowing pretty much anything and the second one pretty much nothing (I'm a man of the extremes what can I say).

Can someone help me fix my validator?

Leonardo

Well, the first problem I see here is the escaping. The backslash is being consumed by the C++ compiler and doesn't get to the regex parser. You need to double escape it, to compensate this issue. Like this:

"^[a-z]+\\.?[a-z]+[0-9]*$"

You said the string can only have one lowercase character, so you need to remove the first +. If both the period and the following characters are optional, they should be grouped.

"^[a-z](\\.[a-z]+)?[0-9]*$"

ealione

@Leonardo said:

"^a-z?[0-9]*$"

Thanks for the quick reply. I can confirm it is working as intended.

SGaist

Hi,

You can check the regularexpression example (available starting 5.5). It's a little application that helps test and build regexp to use with QRegularExpression

ealione

5.5 you say. Interesting :)

SGaist

I do :)

However, you don't need to build Qt 5.5 to build it, you can use your current Qt version