CODEWITHSUNDEEP
regexqt
JasonsBeer
JasonsBeer

Reputation: 19

Qt Regular Expression Escape Sequence Problem

I'm struggling to get a regular expression implemented. I'm using Qt creator on an Ubuntu system. I tested my regex against an example number with a 3rd party tool. So I believe the problem is not with the expression. My desired reg ex:

/\b(9410 ?\d{18})\b/i

I am putting the regex string into a QString variable. Which results in an error:

QString test = "/\b(9410 ?\d{18})\b/i"; unknown escape sequence '\d'

In an attempt to fix, I add an extra \ at the point of the error:

QString test = "/\b(9410 ?\\d{18})\b/i"; qWarning() << test;

Debugger indicates (note the \\):

/\b(9410 ?\\d{18})\b/i

I also tried a raw string:

QString test = R"(/\b(9410 ?\d{18})\b/i)"; qWarning() << test;

Debugger shows all single \ replaced with \\.

/\\b(9410 ?\\d{18})\\b/i

None of these attempts has resulted in a working reg ex. There is something fishy going on with the back slashes. Appreciate your thoughts. I must be missing something simple...

EDIT: Here is some simplified code. When I run this it returns "FALSE" indicating no match. I tested this regex and number at regex101.com. Works there. That's why I believe something is flawed in my implementation. Just can't put my finger on it.

QRegularExpression re;
QString test = R"(/\b(9410 ?\d{18})\b/i)";
re.setPattern(test);
if(re.match("9410811298370146293071").hasMatch())
{
    qWarning() << "TRUE";
}
else {
    qWarning() << "FALSE";
}

Upvotes: 0

Views: 1041

Answers (1)

JasonsBeer
JasonsBeer

Reputation: 19

Cleaned up the regex and it now matches.

QRegularExpression re;
QString test = R"(9410 ?\d{18})";
re.setPattern(test);
if(re.match("9410811298370146293071").hasMatch())
{
    qWarning() << "TRUE";
}
else {
    qWarning() << "FALSE";
}

Upvotes: 1

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