Function to extract domain name from URL in R

I don't know of a function in a package to do this. I don't think there's anything in base install of R. Use a user defined function and store it some where to source later or make your own package with it.

x1 <- "http://stackoverflow.com/questions/19020749/function-to-extract-domain-name-from-url-in-r"
x2 <- "http://www.talkstats.com/"
x3 <- "www.google.com"

domain <- function(x) strsplit(gsub("http://|https://|www\\.", "", x), "/")[[c(1, 1)]]

domain(x3)
sapply(list(x1, x2, x3), domain)
## [1] "stackoverflow.com" "talkstats.com"     "google.com"

You can also use the relatively new urltools package:

library(urltools)

URLs <- c("http://stackoverflow.com/questions/19020749/function-to-extract-domain-name-from-url-in-r",
          "http://www.talkstats.com/", "www.google.com")

suffix_extract(domain(URLs))

##                host subdomain        domain suffix
## 1 stackoverflow.com      <NA> stackoverflow    com
## 2 www.talkstats.com       www     talkstats    com
## 3    www.google.com       www        google    com

It's backed by Rcpp so it's wicked fast (significantly more so than using built- in R apply functions.