Here’s the dataset I’m working with, called test - subject group wk1 wk2 wk3 wk4 place 001-002 boys 2 3 4 5 002-003 boys 7 6 5 4 003-004 boys 9 4 6 1 004-005 girls 5 7 8 9 005-006 girls 2 6 3 8 006-007 girls 1 4 7 4
if I call mutate(test, place = substr(subject,1,3), “001 is the first observation in the place column But it’s a character and “subject” is a factor. I need place to be a factor, too, but I need the observations to be ONLY the first three numbers of “subject.” Does that make my request more understandable? Ken kmna...@gmail.com 914-450-0816 (tel) 347-730-4813 (fax) > On Mar 4, 2016, at 12:49 PM, Sarah Goslee <sarah.gos...@gmail.com> wrote: > > Hi Ken, > > You do that with as.factor(), as has already been suggested. You'll need to > provide a reproducible example to show us what's going wrong. Using fake data > is fine, we just need to see some data that look like yours and the code > you're using. > > Sarah > > On Fri, Mar 4, 2016 at 11:57 AM, KMNanus <kmna...@gmail.com > <mailto:kmna...@gmail.com>> wrote: > Let me see if I can ask the question more clearly - I am trying to extract a > section of a hyphenated factor. For example, 001-004 is one observation of > test$ken, which is a factor, and I want to set up a new factor variable > called place that would have 001 as an observation. If I call mutate(place = > (as.character (test$ken)), I can extract 001 from 001-004, but but don't > know how to subsequently convert that character string back into a factor. > > > Or can 001 be extracted from a factor as a factor? > > Do you know how to execute either of these approaches? > > Ken > kmna...@gmail.com <mailto:kmna...@gmail.com> > 914-450-0816 <tel:914-450-0816> (tel) > 347-730-4813 <tel:347-730-4813> (fax) > > > > > On Mar 3, 2016, at 8:33 PM, Hervé Pagès <hpa...@fredhutch.org > > <mailto:hpa...@fredhutch.org>> wrote: > > > > On 03/03/2016 02:13 PM, KMNanus wrote: > >> When I do that, > > > > When you do what exactly? > > > > It's impossible for anyone here to know what you're doing if you > > don't show the code. > > > >> I get "Error in `$<-.data.frame`(`*tmp*`, "site", value > >> = integer(0)) : > >> replacement has 0 rows, data has 6” > >> > >> The data frame has 6 rows. > > > > You said you had a factor variable, you never mentioned you had a > > data.frame. If the factor variable is part of a data.frame 'df', > > then first extract it with something like df$myvar or df[["myvar"]], > > and then call substr() followed by as.factor() on it. > > > > H. > > > >> > >> Ken > >> kmna...@gmail.com <mailto:kmna...@gmail.com> <mailto:kmna...@gmail.com > >> <mailto:kmna...@gmail.com>> > >> 914-450-0816 <tel:914-450-0816> (tel) > >> 347-730-4813 <tel:347-730-4813> (fax) > >> > >> > >>> On Mar 3, 2016, at 4:52 PM, Hervé Pagès <hpa...@fredhutch.org > >>> <mailto:hpa...@fredhutch.org> > >>> <mailto:hpa...@fredhutch.org <mailto:hpa...@fredhutch.org>>> wrote: > >>> > >>> Hi, > >>> > >>> On 03/03/2016 12:18 PM, KMNanus wrote: > >>>> I have a factor variable that is 6 digits and hyphenated. For > >>>> example, 001-014. > >>>> > >>>> I need to extract the first 3 digits to a new variable using mutate > >>>> in dplyr - in this case 001 - but can’t find a function to do it. > >>>> > >>>> substr will do this for character strings, but I need the variable to > >>>> remain as a factor. > >>> > >>> What prevents you from calling as.factor() on the result to turn it > >>> back into a factor? > >>> > >>> H. > >>> > >>>> > >>>> Is there an R function or workaround to do this? > >>>> > >>>> > >>>> Ken > >>>> kmna...@gmail.com <mailto:kmna...@gmail.com> <mailto:kmna...@gmail.com > >>>> <mailto:kmna...@gmail.com>> > >>>> 914-450-0816 <tel:914-450-0816> (tel) > >>>> 347-730-4813 <tel:347-730-4813> (fax) > >>>> > >>>> > >>>> > >>>> ______________________________________________ > >>>> R-help@r-project.org <mailto:R-help@r-project.org> mailing list -- To > >>>> UNSUBSCRIBE and more, see > >>>> https://stat.ethz.ch/mailman/listinfo/r-help > >>>> <https://stat.ethz.ch/mailman/listinfo/r-help> > >>>> PLEASE do read the posting guide > >>>> http://www.R-project.org/posting-guide.html > >>>> <http://www.r-project.org/posting-guide.html> > >>>> and provide commented, minimal, self-contained, reproducible code. > >>>> > >>> > >>> -- > >>> Hervé Pagès > >>> > >>> Program in Computational Biology > >>> Division of Public Health Sciences > >>> Fred Hutchinson Cancer Research Center > >>> 1100 Fairview Ave. N, M1-B514 > >>> P.O. Box 19024 > >>> Seattle, WA 98109-1024 > >>> > >>> E-mail: hpa...@fredhutch.org <mailto:hpa...@fredhutch.org> > >>> <mailto:hpa...@fredhutch.org <mailto:hpa...@fredhutch.org>> > >>> Phone: (206) 667-5791 <tel:%28206%29%20667-5791> > >>> Fax: (206) 667-1319 <tel:%28206%29%20667-1319> > >> > > > > -- > > Hervé Pagès > > > > Program in Computational Biology > > Division of Public Health Sciences > > Fred Hutchinson Cancer Research Center > > 1100 Fairview Ave. N, M1-B514 > > P.O. Box 19024 > > Seattle, WA 98109-1024 > > > > E-mail: hpa...@fredhutch.org <mailto:hpa...@fredhutch.org> > > Phone: (206) 667-5791 <tel:%28206%29%20667-5791> > > Fax: (206) 667-1319 <tel:%28206%29%20667-1319> > ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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.
