Regular expressions are a powerful in any language to manipulate, search, etc. data.

For example:

> fruit <- c("apple", "banana", "pear", "pineapple")
> fruit
[1] "apple"     "banana"    "pear"      "pineapple"

> grep("a", fruit) # there is an "a" in each of the words
[1] 1 2 3 4
> strsplit("a string", "s") # strsplit splits the string on the "s"
[1] "a "    "tring"

R base has many functions for regular expressions, see slide 9 of Ed’s talk below. The package stringr, created by Hadley Wickham, is a nice alternative that wraps the base regex functions for easier use. I highly recommend stringr.

Ed Goodwin, the coordinator of the Houston R Users group, gave a presentation to the group last night on regular expressions in R. It was a great talk, and he is allowing me to post his talk here.

Enjoy! And thanks for sharing Ed!