regular expression question
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.
Not sure that this is what you mean, but here's an example of removing
all non-A-through-Z characters:
x = c("A.1", "B...2", "C..3..D");
gsub("[^(A-Z)]", "", x)
[1] "A" "B" "CD"
Basically you should look at the character substitution functions sub and gsub.
Peter