Inline. -- Bert Bert Gunter
On Thu, Apr 7, 2016 at 1:25 PM, John Sorkin <jsor...@grecc.umaryland.edu> wrote: > > I would like to apply a function, fract, to the columns of a > dataframe. I tried the following > apply(data5NonEventEpochs,2,fract) > but, no surprise it did not work as apply works on matrices not data > frames. That is false! From ?apply: "If X is not an array but an object of a class with a non-null dim value (such as a data frame), apply attempts to coerce it to an array via as.matrix if it is two-dimensional (e.g., a data frame) or via as.array." Your apply() call would not have worked with a matrix either, as your syntax was wrong. Here is a corrected example: > X <- data.frame(a=1:5,b=6:10) > apply(X,2,function(x)mean(sqrt(x))) a b 1.676466 2.817189 How can I apply a fuction to the columns of a data frame? (I > can't covert data5NonEventsEpochs to a matrix as it contains character > data). > Thank you, > John > John David Sorkin M.D., Ph.D. > Professor of Medicine > Chief, Biostatistics and Informatics > University of Maryland School of Medicine Division of Gerontology and > Geriatric Medicine > Baltimore VA Medical Center > 10 North Greene Street > GRECC (BT/18/GR) > Baltimore, MD 21201-1524 > (Phone) 410-605-7119 > (Fax) 410-605-7913 (Please call phone number above prior to faxing) > > Confidentiality Statement: > This email message, including any attachments, is for ...{{dropped:12}} ______________________________________________ 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.