hi everyone, wondering if you could help me with a novice problem. I have a data frame called subjects with a height and weight variable and want to calculate a bmi variable from the two. i have tried:
attach(subjects) bmi <- (weight)/((height/100)^2) but it comes up with the error: Warning messages: 1: In Ops.factor(height, 100) : / not meaningful for factors 2: In Ops.factor((weight), ((height/100)^2)) : / not meaningful for factors I presume that this means the vectors height and weight are not in numeric form (confirmed by is.numeric) so i changed the code to: bmi <- (as.numeric(weight))/((as.numeric(height)/100)^2) but this just comes up with a result which doesnt make sense i.e. numbers such as 40000 within bmi vector. Ive looked at as.numeric(height)/as.numeric(weight) and these numbers just arnt the same as height/weight which is the reason for the incorrect bmi. Cant anyone tell me where I am going wrong? Its quiet frustrating because I cant understand why a function claiming to convert to numeric would come up with such a bizarre result. -- View this message in context: http://www.nabble.com/help-with-as.numeric-tp23558326p23558326.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ 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.