The sqrt(-A) is evaluated for all A. The result returned is conditional on the first argument but the other two arguments are evaluated on the entire vector.
Kevin -- Kevin E. Thorpe Head of Biostatistics, Applied Health Research Centre (AHRC) Li Ka Shing Knowledge Institute of St. Michael's Assistant Professor, Dalla Lana School of Public Health University of Toronto email: kevin.tho...@utoronto.ca Tel: 416.864.5776 Fax: 416.864.3016 On 2019-12-09, 7:58 AM, "R-help on behalf of rsherry8" <r-help-boun...@r-project.org on behalf of rsher...@comcast.net> wrote: Please consider the following two R statements: A = runif(20, min=-1,max=1) ifelse( A < 0, sqrt(-A), A ) The second statement produces the following error message: rt(-A) : NaNs produced I understand that you cannot take the square root of a negative number but I thought the condition A < 0 would take care of that issue. It appears not to be. What am I missing? Thanks, Bob ______________________________________________ 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. ______________________________________________ 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.