Pattern Matching help
Samir Mishra wrote:
Thanks in advance for any help I can get on this. I'm trying to change variable names between 2 systems - R and old SPSS, Oracle. I'm using the grep() and gsub() commands but I'm getting the following result -
test.dat <- c("a", "b.c", "d.e.f", "p_q,r")
test.dat
[1] "a" "b.c" "d.e.f" "p_q,r"
grep(",", test.dat, value = TRUE, extended = FALSE)
[1] "p_q,r"
grep("_", test.dat, value = TRUE, extended = FALSE)
[1] "p_q,r"
#NOT WHAT I WANT, I EXPECT TO GET ONLY ELEMENTS 2 & 3 RETURNED
grep(".", test.dat, value = TRUE, extended = FALSE)
[1] "a" "b.c" "d.e.f" "p_q,r"
grep("\\.", test.dat, value = TRUE, extended = FALSE)
And similarly, with gsub(), I get -
gsub(",", "_", test.dat, extended = FALSE)
[1] "a" "b.c" "d.e.f" "p_q_r"
gsub("_", ".", test.dat, extended = FALSE)
[1] "a" "b.c" "d.e.f" "p.q,r"
#NOT WHAT I WANT
gsub(".", "_", test.dat, extended = FALSE) #NOT WHAT I WANT
[1] "_" "___" "_____" "_____"
gsub("\\.", "_", test.dat, extended = FALSE)
Am I doing something wrong?
Yes. Think about the "." in regular expressions. Uwe Ligges -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-help-request at stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._