No, substr is vectorized, you just have a typo, you are using a different vector for nchar than you are subsetting.
-- Gregory (Greg) L. Snow Ph.D. Statistical Data Center Intermountain Healthcare greg.s...@imail.org 801.408.8111 > -----Original Message----- > From: r-help-boun...@r-project.org [mailto:r-help-boun...@r- > project.org] On Behalf Of Marc Schwartz > Sent: Friday, April 30, 2010 5:04 PM > To: Sebastian Kruk > Cc: r-help@r-project.org; r-h...@stat.math.ethz.ch > Subject: Re: [R] drop last character in a names'vector > > > On Apr 30, 2010, at 5:44 PM, Sebastian Kruk wrote: > > > Hi, i have a vector filled with names: > > > > [1] Alvaro Adela ... > > [25] Beatriz Berta ... > > ... > > [100000] ... > > > > I would like to drop last character in every name. > > > > I use the next program: > > > > for (i in 1:100000) { > > largo <- nchar(names[i]-1) > > names[i] <- substring (names[i],1,largo] > > } > > > > Is another and faster way of do it? > > > > Thanks, > > > > Sebastián. > > > As is the case with R, more than one, but the fastest may be: > > names <- c("Alvaro Adela", "Beatriz Berta") > > > gsub("^(.*).{1}$", "\\1", names) > [1] "Alvaro Adel" "Beatriz Bert" > > > Just to show that it works with entries of varying lengths: > > > gsub("^(.*).{1}$", "\\1", c("ABC", "ABCD", "ABCDE", "ABCDEF")) > [1] "AB" "ABC" "ABCD" "ABCDE" > > > See ?gsub and ?regex > > > > You could use substr(), but the arguments for substring lengths are not > vectorized, so the following won't work: > > > substr(c("ABC", "ABCD", "ABCDE", "ABCDEF"), 1, nchar(names) - 1) > [1] "ABC" "ABCD" "ABCDE" "ABCDEF" > > > You would have to do something like this: > > > as.vector(sapply(c("ABC", "ABCD", "ABCDE", "ABCDEF"), > function(x) substr(x, 1, nchar(x) - 1))) > [1] "AB" "ABC" "ABCD" "ABCDE" > > > See ?substr and ?nchar > > HTH, > > Marc Schwartz > > ______________________________________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting- > guide.html > and provide commented, minimal, self-contained, reproducible code. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
