[R] Subsetting Method [ Revisited

Gregory Wall gdwall at ucdavis.edu
Thu Jan 10 00:59:48 CET 2008

Hello Everyone:

As usual, thanks in advance for any help. 

I was hoping to get some more advice on this question:

I'm trying to write a subsetting routine for an S3 object I've created --
lets call it myObject. 

myObject has a few attributes basically of type string and numerics. Its
atomic value is just a vector of ints.

I want to write my own subsetting routine to subset myObject in an
unconventional way.

So my method looks like this:

"[.myObject" <- function( obj, i, j, ...){

..... parameter checking and calculations....



If I call this method in an R session I get the following results:

obj <- "an instance of a myObject"



Error: index of length zero.

I'm not sure how to prevent it from printing twice. I don't understand why
"print.default() is returning what it was asked to print, which then gets
printed again automatically" as was mentioned in a previous thread. 

Does the solution involve creating a child class as mentioned here:


I'm having a difficult time following the execution steps for this R code:


Again, thanks very much for any suggestions.

More information about the R-help mailing list