Hi All,
I've been successfully using the with function for analyses and the
transform function for multiple transformations. Then I thought, why not
use "with" for both? I ran into problems & couldn't figure them out from
help files or books. So I created a simplified version of what I'm
doing:
rm( list=ls() )
x1<-c(1,3,3)
x2<-c(3,2,1)
x3<-c(2,5,2)
x4<-c(5,6,9)
myDF<-data.frame(x1,x2,x3,x4)
rm(x1,x2,x3,x4)
ls()
myDF
This creates two new variables just fine"
transform(myDF,
sum1=x1+x2,
sum2=x3+x4
)
This next code does not see sum1, so it appears that "transform" cannot
see the variables that it creates. Would I need to transform new
variables in a second pass?
transform(myDF,
sum1=x1+x2,
sum2=x3+x4,
total=sum1+sum2
)
Next I'm trying the same thing using "with". It doesn't not work but
also does not generate error messages, giving me the impression that I'm
doing something truly idiotic:
with(myDF, {
sum1<-x1+x2
sum2<-x3+x4
total <- sum1+sum2
} )
myDF
ls()
Then I thought, perhaps one of the advantages of "transform" is that it
works on the left side of the equation without using a longer name like
myDF$sum1. "with" probably doesn't do that, so I use the longer form
below. It also does not work and generates no error messages.
# Try it again, writing vars to myDF explicitly.
# It generates no errors, and no results.
with(myDF, {
myDF$sum1<-x1+x2
myDF$sum2<-x3+x4
myDF$total <- myDF$sum1+myDF$sum2
} )
myDF
ls()
I would appreciate some advice about the relative roles of these two
functions & why my attempts with "with" have failed.
Thanks!
Bob
=========================================================
Bob Muenchen (pronounced Min'-chen), Manager
Statistical Consulting Center
U of TN Office of Information Technology
200 Stokely Management Center, Knoxville, TN 37996-0520
Voice: (865) 974-5230
FAX: (865) 974-4810
Email: [EMAIL PROTECTED]
Web: http://oit.utk.edu/scc,
News: http://listserv.utk.edu/archives/statnews.html
______________________________________________
R-help@stat.math.ethz.ch 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.
