[R] performing function on data frame

[Mike Lawrence]

As Michael notes, scale is what you want. Also, your request has an
incorrect definition of z scores:

d$y - mean(d$y)/sd(d$y) #incorrect

(d$y - mean(d$y) ) / sd(d$y) #correct

On Thu, Apr 16, 2009 at 7:40 AM, Michael Conklin
<michael.conklin at markettools.com> wrote:
> newDF<-as.data.frame(scale(oldDF))
>
> see ?scale
>
> Hope that helps.
>
> Michael Conklin
>
>
> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On Behalf Of Karin Lagesen
> Sent: Thursday, April 16, 2009 5:29 AM
> To: r-help at r-project.org
> Subject: Re: [R] performing function on data frame
>
> David Hajage <dhajage.r at gmail.com> writes:
>
>> Hi Karin,
>>
>> I'm not sure I understand... Is this what you want ?
>>
>> d$y - mean(d$y)/sd(d$y)
>
>
>
>
> Yes, and also a bit no.
>
> Each column in my data frame represents one data set. For every
> element in this data set I want to know the z value for that
> element. I.e: I want to create a new data frame from the old data
> frame, where each element in the new data frame is
>
> newDF[i,j] = oldDF[i,j] - mean(d[,j]) / sddev(d[,j])
>
> I could, I think, iterate like this over the data frame, but I keep
> thinking that one of the apply functions should be employed...
>
> Karin
> --
> Karin Lagesen, Ph.D.
> karin.lagesen at medisin.uio.no
> http://folk.uio.no/karinlag
>
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> ______________________________________________
> R-help at r-project.org mailing list
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> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>



-- 
Mike Lawrence
Graduate Student
Department of Psychology
Dalhousie University

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