[R] regular expression question

[Joshua Wiley]

Hi Erin,

Please read ?grep.  It is clearly not the function you want (neither
is strsplit() either really).  This does what you want and you can
modify for upper/lower case if you need it.  Also note that regular
expressions exist separate from R, so while ":" may have seemed
natural to select a range in R, it has a very different function in
regexp.

gsub("[^A-Za-z]", "", names(funky))

Best regards,

Josh

On Mon, Apr 11, 2011 at 10:49 PM, Erin Hodgess <erinm.hodgess at gmail.com> wrote:
> Dear R People:
>
> I have a data frame with the following column names:
>
>> names(funky)
>  [1] "UHD.1"   "UHD.2"   "UHD.3"   "UHD.4"   "L..W..1" "L..W..2" "L..W..3"
>  [8] "L..W..4" "B..W..1" "B..W..2" "B..W..3" "B..W..4" "W..B..1" "W..B..2"
> [15] "W..B..3" "W..B..4" "B..G..1" "B..G..2" "B..G..3" "B..G..4"
>
>
> I would like to extract the letters from them; no periods, no numbers.
>
> I tried the following:
>
>> grep("[A:Z]",names(funky))
> integer(0)
>
> But this doesn't do it.
>
> I've also been experimenting with strsplit, but no luck yet.
>
> Any help would be much appreciated.
>
> Thanks,
> Sincerely,
> Erin
>
>
> --
> Erin Hodgess
> Associate Professor
> Department of Computer and Mathematical Sciences
> University of Houston - Downtown
> mailto: erinm.hodgess at gmail.com
>
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>



-- 
Joshua Wiley
Ph.D. Student, Health Psychology
University of California, Los Angeles
http://www.joshuawiley.com/