On Wed, May 2, 2012 at 4:34 AM, Jim Lemon <j...@bitwrit.com.au> wrote: > On 05/02/2012 10:47 AM, Eve Proper wrote: >> >> I am a raw novice to R, playing around with a mini .csv dataset created in >> Excel. I can read it in and the data looks OK in Excel and upon initial >> inspection in R: >> >> hikes<- read.csv("/Users/eproper/Desktop/hikes.csv", header=TRUE) >> print(hikes) >> >> does exactly what it is supposed to do. >> >> Two of the variables are genuine strings, but the others ought to be >> numeric, and R will calculate their min, max etc. However, is.numeric >> returns FALSE for all of them; storage.mode returns "language." as.numeric >> returns "Error: 'pairlist' object cannot be coerced to type 'double'." In >> what I suspect is a related problem, any command that calls for a variable >> name requires an initial ~ to work. That is, instead of plot(miles) I have >> to use plot(~miles). >> >> No doubt there is some very elementary mistake I am making, but I can't >> figure it out. Any help would be appreciated. >> > Hi Eve, > Have you tried "as.numeric" on them? As Jeff suggested, you may be importing > spaces along with the digits or some other character that changes the class > of the variable. Also note that the default behavior of functions like > read.csv is to coerce all of the values in a column of the resulting data > frame to the "lowest common denominator". If you have one text value in a > column of numbers, you usually get factor values. This is due to the > restriction that all values in a column must be of the same class (data > type). > > Jim >
If accidentally coerced to factors, the OP might prefer as.numeric(as.character(x)) to get the apparent numeric values rather than the internal ones. Also seconded Jeff's advice about str() Michael ______________________________________________ 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.