Genius,

That certainly is much faster that what I had worked out on my own.

I looked at sweep, but couldn't understand the rather thin help page.  
Your example makes it really clear

Thank You!!!

--
Noah


On 9/11/09 1:57 PM, Gavin Simpson wrote:
> On Fri, 2009-09-11 at 13:10 -0700, Noah Silverman wrote:
>    
>> Hi,
>>
>> Is there an alternative to the scale function where I can specify my own
>> mean and standard deviation?
>>      
> A couple of calls to sweep?
>
> See ?sweep
>
> set.seed(123)
> dat<- data.frame(matrix(runif(10*10), ncol = 10))
> xbar<- colMeans(dat)
> sigma<- apply(dat, 2, sd)
>
> dat.std<- sweep(sweep(dat, 2, xbar, "-"), 2, sigma, "/")
>
> ## compare
> scale(dat)
>
> HTH
>
>    
>> I've come across an interesting issue where this would help.
>>
>> I'm training and testing on completely different sets of data.  The
>> testing set is smaller than the training set.
>>
>> Using the standard scale function of R seems to introduce some error.
>> Since it scales data WITHIN the set, it may scale the same number to
>> different value since the range in the training and testing set may be
>> different.
>>
>> My thought was to scale the larger training set of data, then use the
>> mean and SD of the training data to scale the testing data according to
>> the same parameters.  That way a number will transform to the same
>> result regardless of whether it is in the training or testing set.
>>
>> I can't be the first one to have looked at this.  Does anyone know of a
>> function in R or if there is a scale alternative where I can control the
>> parameters?
>>
>> Thanks!
>>
>> --
>> Noah
>>
>> ______________________________________________
>> R-help@r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>>      

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