Warning: ignored non function "scale"

[Peter Dalgaard BSA]

Paul Gilbert <pgilbert@bank-banque-canada.ca> writes:

> 
> I've been working on a revised version of prcomp and princomp. Below is my
> current draft of prcomp,  which is marginally different from V&R. I've added
> center and scale as optional arguments. However, scale causes the following:
> 
> > zi _ prcomp(iris[,,2])
> Warning: ignored non function "scale"
> 
> because scale is both a variable and a function. Is there any way to avoid this
> error message and still keep the name scale for both the argument and the name
> of the function?

There are several. One, which has been used in other parts of R is to
lengthen the formal argument a bit, e.g. "scale.it" which - since
there's no "..." part can be truncate to, say, "scale". 

Another option is to explicitly fetch the function scale() using
get("scale","package:base") or get("scale",envir=.GlobalEnv). Anything
not including the functions local variables should do the trick.

Actually, I think that the first of the above get()s needs to be 

get("scale",match("package:base",search()))

hmmm, shouldn't we make pos.to.env accept character variables?


> prcomp <- function(x, retx=TRUE, center=TRUE, scale=FALSE) {
>  s <- svd(scale(x, center=center, scale=scale),nu=0)
> # rank <- sum(s$d > 0)
>  rank <- sum(s$d > (s$d[1]*sqrt(.Machine$double.eps)))
>  if (rank < ncol(x)) s$v <- s$v[,1:rank]
>  s$d <- s$d/sqrt(max(1,nrow(x) -1))
>  if(retx) list(sdev=s$d, rotation=s$v, x=x %*% s$v)
>  else     list(sdev=s$d, rotation=s$v)
> }

-- 
   O__  ---- Peter Dalgaard             Blegdamsvej 3  
  c/ /'_ --- Dept. of Biostatistics     2200 Cph. N   
 (*) \(*) -- University of Copenhagen   Denmark      Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard@biostat.ku.dk)             FAX: (+45) 35327907

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