[R] Regular expressions & sub

[Bernd Weiss]

On 18 Aug 2005 at 21:17, Peter Dalgaard wrote:

> Dirk Eddelbuettel <edd at debian.org> writes:
> 
> > Bernd Weiss <bernd.weiss <at> uni-koeln.de> writes:
> > > I am struggling with the use of regular expression. I got
> > > 
> > > > as.character(test$sample.id)
> > >  [1] "1.11"   "10.11"  "11.11"  "113.31" "114.2"  "114.3"  "114.8"
> > >   
> > > 
> > > and need
> > > 
> > > [1] "11"   "11"  "11"  "31" "2"  "3"  "8"
> > > 
> > > I.e. remove everything before the "." .
> > 
> > Define the dot as the hard separator, and allow for multiple digits
> > before it:
> > 
> > > sample.id <- c("1.11", "10.11", "11.11", "113.31", "114.2",
> > > "114.3", "114.8") gsub("^[0-9]*\.", "", sample.id)
> > [1] "11" "11" "11" "31" "2"  "3"  "8" 
> 
> Or, more longwinded, but with less assumptions about what goes before
> the dot:
> 
> > gsub("^.*\\.(.*)$","\\1",sample.id)
> [1] "11" "11" "11" "31" "2"  "3"  "8"

Wow, thanks a lot for all the valuable suggestions.

Bernd