R talk on regular expressions (regex)

October 6, 2011
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(This article was first published on Recology, and kindly contributed to R-bloggers)

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]]
[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!



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