Regular expressions & sub

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"