[R] unexpected input in rpart

[Petr Savicky]

On Thu, Dec 30, 2010 at 07:10:33AM -0800, maysher wrote:
> 
> Hi all, I'm a newbee using R. I need to do a classification tree using the
> rpart package. Basically I have a set of birds of known sex and several
> morphological measurements and we want to predict the sex using the
> morphology. I read my csv file and it shows up in R no problem, looks fine
> but when I execute the following rpart command 
> 
> hawkadults_rpart<-rpart(Sex∼Footpad+Mean_2ndlength+Bill_length+Tarsus_reg+Mass+Wing_chord,method="class",data=hawkadultsDF)
> 
> I get the message Error: unexpected input in "hawkadults_rpart<-rpart(Sex‚"

The formula in your input contains a tilda character, which is not the
ASCII tilda (7E), but some other UTF-8 character (E2 88 BC). For
comparison, the two characters are "~" and "∼" (in the same order). Which
of these two was in your actual R code? In a formula, the ASCII tilda is
required.

Petr Savicky.