Question

Can any one suggest me how to validate strings separated by dot (.) in QT basically just like package name in java,

My code goes like this

QRegExp rx("^[\\w]+[^\\.{0,1}\\w+$]*$");
rx.setCaseSensitivity(Qt::CaseInsensitive);
return rx.exactMatch(package);

but I am getting wrong results

Ex:

 com.me.test // valid
 com.me.he. // invalid
 .com.me.he // invalid
 com..me.me // invalid

Answer 1

Thats because of your wrong use of a character class. Characters that are between square brackets are a character class, so

 [^\\.{0,1}\\w+$]*

is a negated character class, because it starts with a ^. This class will match any character that is not one of those characters: “.{},01+$” or that is not in \w.

What you want sounds more like

^\\w+(\\.\\w+)*$

See it here on Regexr

And by the way, you don’t need the CaseInsensitive option, because you don’t have explicitly written letters in your regex.