Re: [Boost-users] Boost.Regex: regex_replace with named captures/groups

Subject: Re: [Boost-users] Boost.Regex: regex_replace with named captures/groups
From: NoRulez (norulez_at_[hidden])
Date: 2012-01-31 05:41:27

Hello John,

sorry, I made a copy/paste mistake. The lines should be as followed:

FALSE:
std::string data = "Today is the 2012-01-31";
std::string replace = "\\5\\g{sep}\\4\\g{sep}\\1\\2";
std::string pattern = "(19|20)(\\d\\d)(?<sep>[- /.])(0[1-9]|1[012])\\g{sep}(0[1-9]|[12][0-9]|3[01])";
boost::regex rx(pattern);

std::string replaced = boost::regex_replace(data, rx, replace);

RESULT: "Today is the 31g{sep}01g{sep}2012"

If I use numbers instead of named groups as followed it works:

CORRECT:
std::string data = "Today is the 2012-01-31";
std::string replace = "\\5\\3\\4\\3\\1\\2";
std::string pattern = "(19|20)(\\d\\d)([- /.])(0[1-9]|1[012])\\3(0[1-9]|[12][0-9]|3[01])";
boost::regex rx(pattern);

std::string replaced = boost::regex_replace(data, rx, replace);

RESULT: "Today is the 31-01-2012"

Best Regards
NoRulez

Am 31. Jan 2012 um 09:41 schrieb John Maddock <boost.regex_at_[hidden]>:

> > does boost's regex_replace not recognize named captures/groups or did I
> > something wrong?
>
> Yes it does, but remember that the C++ compiler gobbles up the \'s before
> regex gets to se those strings, so use \\ everywhere and you should be fine.
>
> HTH, John.
>
> > std::string date = "2012/01/30";
> > std::string replace = "\5\g{separator}\4\g{separator}\1\2"; // should be
> > => 30/01/2012
> > boost::regex
> > rx("^(19|20)(\d\d)(?<separator>[/.])(0[1-9]|1[012])\g{separator}(0[1-9]|[12][0-9]|3[01])$");
> >
> > std::string replaced = boost::regex_replace(date, rx, replace);
> >
> > The content in "replaced" is now "30\g{separator}01\g{separator}2012"
> >
> > Thanks in advance
> >
> > Best Regards
> > NoRulez
> > _______________________________________________
> > Boost-users mailing list
> > Boost-users_at_[hidden]
> > http://lists.boost.org/mailman/listinfo.cgi/boost-users
>
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