[R] Leave one out procedure - R

[Vyshnnavi Parthasarathy]

Hello,
Thanks John and David. I ll look into your suggestions and I ll ensure I
post more details the next time.

Thanks,
Vyshnnavi
On Jul 7, 2015 8:19 AM, "David L Carlson" <dcarlson at tamu.edu> wrote:

> As John suggests, more information and some sample data would help. I
> haven't used loocv, but here is a simple example of leave one out cross
> validation with simple linear regression. This does not eliminate the loop,
> but uses lapply() which makes specifying the loop simpler. The results of
> the 40 regressions are stored in a list called results and results.coef
> contains the intercept and slope for each regression in a matrix.
>
> > set.seed(42)
> > x <- rnorm(40, 10, 2)
> > y <- x + rnorm(40, 0, 2)
> > results <- lapply(1:40, function(i) lm(y[-i] ~ x[-i]))
> > results.coef <- t(sapply(results, coef))
> > summary(results.coef)
>   (Intercept)          x[-i]
>  Min.   :-0.1477   Min.   :0.8408
>  1st Qu.: 0.2032   1st Qu.:0.9830
>  Median : 0.2613   Median :0.9883
>  Mean   : 0.2933   Mean   :0.9866
>  3rd Qu.: 0.3240   3rd Qu.:0.9959
>  Max.   : 1.9160   Max.   :1.0245
>
> -------------------------------------
> David L Carlson
> Department of Anthropology
> Texas A&M University
> College Station, TX 77840-4352
>
> -----Original Message-----
> From: R-help [mailto:r-help-bounces at r-project.org] On Behalf Of John Kane
> Sent: Monday, July 6, 2015 6:53 PM
> To: Vyshnnavi Parthasarathy; r-help at r-project.org
> Subject: Re: [R] Leave one out procedure - R
>
>
> Hi Vyshnnavi,
>
> I'd suggest having a look at
> http://stackoverflow.com/questions/5963269/how-to-make-a-great-r-reproducible-example
> and http://adv-r.had.co.nz/Reproducibility.html for some hints on how to
> ask questions on the R-help List.
>
> At the moment I don't think you have supplied enough information, code,
> and data for people to easily answer your questions.
>
> BTW if you are supplying sample data the best way is to use the dput()
> function. It provides an exact copy of the data set that you are working
> with.
>
> Sorry not to be of any substantive help.
>
>
>
> John Kane
> Kingston ON Canada
>
>
> > -----Original Message-----
> > From: vyshnnaviammu at gmail.com
> > Sent: Mon, 6 Jul 2015 08:56:52 -0700
> > To: r-help at r-project.org
> > Subject: [R] Leave one out procedure - R
> >
> > Hello,
> > I am still in the process of familiarizing myself with R, pardon me if
> > this
> > is basic. I want to run a leave one out procedure for a 40 member
> > dataset.
> > At the moment I am doing it via a simple for loop. I wanted to know if
> > there is a superior way to do it. I read about the loocv command here -
> > http://artax.karlin.mff.cuni.cz/r-help/library/DMwR/html/loocv.html.
> > Since
> > I need to save the output generated in each iteration, I am not very sure
> > how exactly to implement the same using the loocv command. If you could
> > give me an insight into how to do it/ suggest quicker ways to do leave
> > one
> > out cross validation, it would be really helpful!
> >
> > Thanks,
> > Vyshnnavi
> >
> >       [[alternative HTML version deleted]]
> >
> > ______________________________________________
> > R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> > 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.
>
> ____________________________________________________________
> GET FREE 5GB EMAIL - Check out spam free email with many cool features!
> Visit http://www.inbox.com/email to find out more!
>
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> 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.
>

	[[alternative HTML version deleted]]