Utility function to apply a scale object on another data frame

Thanks, Joshua. This is exactly what I was looking for.
Hi "e",

Here is a simple function to use the attributes from one scaled object
to scale another.

x = data.frame(a=1:10,b=11:20)
y = data.frame(a=2:11,b=12:21)
s <- scale(x)

## function to scale x using attributes from trained
scale2 <- function(x, trained) {
?x <- as.matrix(x)
?x <- sweep(x, 2L, attr(trained, "scaled:center"), FUN = "-")
?x <- sweep(x, 2L, attr(trained, "scaled:scale"), FUN = "/")
?attr(x, "scaled:center") <- attr(trained, "scaled:center")
?attr(x, "scaled:scale") <- attr(trained, "scaled:scale")
?return(x)
}

## scale y from s
scale2(y, s)

HTH,

Josh

On Sat, Jul 16, 2011 at 1:08 AM, E- Cognium <ecognium at gmail.com> 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'

Thanks,
-e

? ? ? ?[[alternative HTML version deleted]]

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Joshua Wiley
Ph.D. Student, Health Psychology
University of California, Los Angeles
https://joshuawiley.com/

Utility function to apply a scale object on another data frame

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