Hi Henrique, I believe your solution is wrong as it is fitted to find 12ab3, whereas Yan seems to be asking for the characters after the second underscore and before the third underscore.
For example, gsub(".*_.*_(.*)_.*", "\\1", "abcd_efgh_XXXXX_12ab3_dfsfd") would still yield 12ab3 even though, as I understand it, it should have output XXXXX. I think a straightforward solution would do the job: strsplit("abcd_efgh_12ab3_dfsfd", "_")[[1]][3] strsplit("abcd_efgh_XXXXX_12ab3_dfsfd", "_")[[1]][3] has the output XXXXX, for example. Of course, I would be wrong if Yan specifically wanted to find the string 12ab3. But in that case, he would have been asking for matching (and locating) that substring instead of extracting it. Regards, Soumendra -- Soumendra Prasad Dhanee Quantitative Analyst, Neural Technologies and Software Pvt. Ltd. soumen...@neuraltechsoft.com, soumen...@maths.org.in, soumen...@gmail.com +91-7498076111, +91-8100428686 -- "When you understand why you dismiss all the other possible gods, you will understand why I dismiss yours." - Stephen Roberts On 10 February 2011 11:52, Henrique Dallazuanna <www...@gmail.com> wrote: > Try this: > > gsub(".*_.*_(.*)_.*", "\\1", "abcd_efgh_12ab3_dfsfd") > > On Thu, Feb 10, 2011 at 9:42 AM, Yan Jiao <y.j...@ucl.ac.uk> wrote: > >> Dear R gurus, >> >> >> >> If I got a vector with string characters like "abcd_efgh_12ab3_dfsfd", >> how could I extract "12ab3", which is the characters after second >> underscore and before the third underscore? >> >> >> >> Tons of thanks >> >> >> >> yan >> >> >> >> >> >> >> ********************************************************************** >> This email and any files transmitted with it are confide...{{dropped:10}} >> >> ______________________________________________ >> R-help@r-project.org mailing list >> 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. >> > > > > -- > Henrique Dallazuanna > Curitiba-Paraná-Brasil > 25° 25' 40" S 49° 16' 22" O > > [[alternative HTML version deleted]] > > > ______________________________________________ > R-help@r-project.org mailing list > 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. > > ______________________________________________ R-help@r-project.org mailing list 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.