[R] body of non-visible function

[Liaw, Andy]

> From: Anna Oganyan
> 
> Hello,
> Is there any possibility in R to see the body of the "non-visible" 
> function, for
> example "princomp"?
> If I do :
> 
>  > methods(princomp)
> 
> so, I get that princomp.default and princomp.formula are non-visible 
> functions and
> body(princomp.default) doesn't show it.

You may want to learn about getAnywhere() and getS3method().

 
> In particular, I guess I have a very naïve question...
> I'd like to see how scores calculation is implemented in the function
> princomp. Because when I multiply my data matrix on the 
> matrix of loadings
>  >data.matrix %*% princomp(data.matrix, scores=T)$loadings
> 
> I get different result than just doing
> 
>  >princomp(data.matrix, scores=T)$scores.

Variables are centered and scaled, so you want to do

  scale(data.matrix) %*% loadings(princomp(data.matrix))

Andy

 
> Thanks.
> Anna
> 
> ______________________________________________
> R-help at 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
> 
> 
>