[R] Utility function to apply a scale object on another data frame

[David Winsemius]

On Jul 16, 2011, at 4:08 AM, E- Cognium wrote:

> Hi Everyone,
>
> I would like to scale a data frame and then using the same scaling
> parameters scale on another data frame. This will be helpful in  
> scaling the
> test dataset based on train dataset's scaling parameters. I couldn't  
> find
> any utility functions that do this. Any suggestions on how to  
> approach this
> problem?
>
> x = data.frame(a=1:10,b=11:20)
> y = data.frame(a=2:11,b=12:21)
> s <- scale(x)
> ###
> ### would like scale 'y' using the parameters contained in 's'

Just look at s and consult the obvious help page...
?attr

attr(s,"scaled:center")
attr(s,"scaled:scale")

-- 
David Winsemius, MD
West Hartford, CT