[R] How to remove multiple outliers

[R. Michael Weylandt]

I believe Dr. Winsemius addressed this in your other thread, but I
would hesitate to do any sort of outlier identification based on
repeated application of a filter (for that matter, I'm not much of an
outlier removal guy generally, but let's suppose I were). You can
easily get into a situation where those data that were not outliers
previously now become so. Rather a single pass filter is probably more
appropriate....even better would be to use some robust methodologies,
such as those made available in library(robustbase).

As to the technical bits of your question,

I can't easily get rm.outlier to throw an error like that: can you
provide a minimum working example that does?

I'm not aware of any simple direct method for repeated function
application other than a loop trick. Perhaps one could rig something
with do.call() but the loop should be fine.

Michael

On Fri, Oct 21, 2011 at 6:40 AM, aajit75 <aajit75 at yahoo.co.in> wrote:
> Hi Michael,
>
> Thanks for the help.
>
> Yes, I have gone through the document for ?outlier. As it removes one
> outlier at a time, being new to R, I was woondering is there any function
> available for removing multiple outliers whithout calling say rm.outlier for
> n number of time because n is not finite here.
>
> On the second point, I am using below mentioned piece of code, because I am
> getting error when rm.outlier with fill = FALSE option is applied on the
> same dataset.
>
> outlier_tf1 = outlier(x1,logical=TRUE)
> find_outlier1 = which(outlier_tf1==TRUE, arr.ind=TRUE)
> beh_input_ro1 = x1[-find_outlier1]
>
>> library(outliers)
>> beh_input_ro <- rm.outlier(beh_input_dr, fill = FALSE, median = FALSE,
>> opposite = FALSE)
> Error in data.frame(X1 = c(28.7812, 24.8923, 31.3987, 25.774, 27.1798,  :
> arguments imply differing number of rows: 2398, 2390, 2399
>
> Regards,
> -Ajit
>
> --
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