Extract a regular expression match in R version 2.10
- by tovare
Hi,
I'm trying to extract a number from a string.
And do something like this [0-9]+ on this string "aaaa12xxxx" and get "12".
I thought it would be something like:
> grep("[0-9]+","aaa12xxx", value=TRUE)
[1] "aaa12xxx"
And then I figured...
> sub("[0-9]+", "\\1", "aaa12xxxx")
[1] "aaa12xxx"
But I got some form of response doing:
> sub("[0-9]+", "ARGH!", "aaa12xxxx")
[1] "aaaARGH!xxx"
There's a small detail I'm missing Please advice :-)
I'm using R version 2.10.1 (2009-12-14)
Thanks !
Comments on the solution
The best solution is to ignore the standard functions and install Hadley Wickham's stringr package to get something that actually makes sense.
Kudos to Marek for figuring out how the standard library worked.