Use regexpr to get the offset into the string and its length and then use substr to pick extract it.
On Sat, Jan 2, 2010 at 10:43 AM, johannes rara <johannesr...@gmail.com> wrote: > Thanks, is the same possible using basic gsub/sub/grep etc. functions? > > -J > > 2010/1/2 Gabor Grothendieck <ggrothendi...@gmail.com>: >> Try this which uses a slightly simpler regexp: >> >>> library(gsubfn) >>> strapply(txt, "(\\d{1,2}\\.\\d{1,2}\\.\\d{4}).*")[[1]] >> [1] "05.12.2009" >> >> or we could convert it to Date class at the same time where we have >> assumed month.day.year: >> >>> strapply(txt, "(\\d{1,2}\\.\\d{1,2}\\.\\d{4}).*", ~ as.Date(x, >>> "%m.%d.%Y"))[[1]] >> [1] "2009-05-12" >> >> or this even simpler regexp extracting all the dates and then picking >> off the first: >> >>> strapply(txt, "\\d{1,2}\\.\\d{1,2}\\.\\d{4}")[[1]][1] >> [1] "05.12.2009" >> >> On Sat, Jan 2, 2010 at 10:08 AM, johannes rara <johannesr...@gmail.com> >> wrote: >>> I would like to extract first date from a string: >>> >>>> txt <- "first date is 05.12.2009. Second date is 06.12.2009." >>>> txt >>> [1] "first date is 05.12.2009. Second date is 06.12.2009." >>> >>> I tried: >>> >>>> sub("^.*?\\s(\\d{1,2}\\.\\d{1,2}\\.\\d{4})", "\\1", txt, extended=T, >>>> perl=T) >>> [1] "05.12.2009. Second date is 06.12.2009." >>>> >>> >>> How to modify this? >>> >>> -J >>> >>> ______________________________________________ >>> 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.