R regex find last occurrence of delimiter

Question

I\'m trying to get the ending for email addresses (ie .net, .com, .edu, etc.) but the portion after the @ can have multiple periods.

library(stringi)

stri         


        

Answer 1

A read.table + file_ext approach (not regex but pretty easy):

dat <- read.table(text=strings1, sep="@")
dat$V3 <- tools::file_ext(strings1)
dat

##     V1            V2  V3
## 1 test       aol.com com
## 2 test   hotmail.com com
## 3 test    xyz.rr.edu edu
## 4 test abc.xx.zz.net net

Here's a purely regex approach:

do.call(rbind, strsplit(strings1, "@|\\.(?=[^\\.]+$)", perl=TRUE))

##     [,1]   [,2]        [,3] 
## [1,] "test" "aol"       "com"
## [2,] "test" "hotmail"   "com"
## [3,] "test" "xyz.rr"    "edu"
## [4,] "test" "abc.xx.zz" "net"