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 <johannesraja at 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."