> On 30 Nov 2015, at 13:09, Abhinaba Roy <[email protected]> wrote: > > Hey, > > worked like a charm! :) > > Could you please explain about > > sub("^([0-9]*).*$", "\\1", fields) >
Yes. sub() replaces substrings. The first argument captures the interesting part of the string: ^ = start of the string, ([0-9]*) = capture of the interesting part of the string. [0-9] means any figure from 0 to 9. * means 1 or more of these characters, and () is used to capture the substring, .* = all the rest. Dot (.) means any character, and * means again one or more of these characters, $ = the end of the string. The whole regular expression matches the whole string and captures the interesting part inside the (). The second argument is the replacement. //1 means the first captured substring. Thus, globally, we replace the whole string by the captured substring. Best, Philippe Grosjean > Thanks, > Abhinaba > > On Mon, Nov 30, 2015 at 4:47 PM, <[email protected] > <mailto:[email protected]>> wrote: > fields <- c("2154333b-3208-4519-8b76-acaef5b5a479", > "980958a0-103b-4ba9-afaf-27b2f5c24e69", > "00966654-0dea-4899-b8cf-26e8300b262d") > sub("^([0-9]*).*$", "\\1", fields) > > Best, > > Philippe Grosjean > > > On 30 Nov 2015, at 11:39, Abhinaba Roy <[email protected] > > <mailto:[email protected]>> wrote: > > > > Hi, > > > > I have a field with alpha numeric codes like, > > > > 2154333b-3208-4519-8b76-acaef5b5a479 980958a0-103b-4ba9-afaf-27b2f5c24e69 > > 00966654-0dea-4899-b8cf-26e8300b262d > > I want a derived field which will contain ONLY the numeric part before the > > first alphabet and the first '-', > > > > for example the derived field from the sample above will give me > > > > 2154333 > > 980958 > > 00966654 > > > > How can this be achieved in R? > > > > P.S. I do not have much knowledge on regex. It would be of great help if > > you could suggest some reading for beginners. > > > > Thanks, > > Abhinaba > > > > [[alternative HTML version deleted]] > > > > ______________________________________________ > > [email protected] <mailto:[email protected]> mailing list -- To > > UNSUBSCRIBE and more, see > > https://stat.ethz.ch/mailman/listinfo/r-help > > <https://stat.ethz.ch/mailman/listinfo/r-help> > > PLEASE do read the posting guide > > http://www.R-project.org/posting-guide.html > > <http://www.r-project.org/posting-guide.html> > > and provide commented, minimal, self-contained, reproducible code. > > [[alternative HTML version deleted]] ______________________________________________ [email protected] mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
