R help - Sep 2009 - How to return/show the indexes of unusual points in boxplot?

I am wondering if you know how to return by function or show in boxplot,
the indexes of unusual points, such as,
points that are outside the box or in [Q3+1.5IQR,Max].
For example,
> boxplot(c(4,rnorm(20),8))
There are 2 unusual points 4 and 8. How to show the indexes of 4 and 8 in
the boxplot
or return them by function?

Thanks,

-james

Try this:

bp <- boxplot(c(4,rnorm(20),8))
bp$out


On Wed, Sep 9, 2009 at 4:25 PM, <guox@ucalgary.ca> wrote:
> I am wondering if you know how to return by function or show in boxplot,
> the indexes of unusual points, such as,
> points that are outside the box or in [Q3+1.5IQR,Max].
> For example,
>
> > boxplot(c(4,rnorm(20),8))
>
> There are 2 unusual points 4 and 8. How to show the indexes of 4 and 8 in
> the boxplot
> or return them by function?
>
> Thanks,
>
> -james
>
> ______________________________________________
> 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.
>


-- 
Henrique Dallazuanna
Curitiba-Paraná-Brasil
25° 25' 40" S 49° 16' 22" O

	[[alternative HTML version deleted]]

boxplot returns a dataframe that has the values in it at "$out":
> x <- boxplot(c(4,rnorm(20),8))
> x
$stats
           [,1]
[1,] -1.5364498
[2,] -0.5282799
[3,] -0.1398736
[4,]  0.3065579
[5,]  1.3430388

$n
[1] 22

$conf
           [,1]
[1,] -0.4210947
[2,]  0.1413474

$out
[1] 4 8

$group
[1] 1 1

$names
[1] "1"



On Wed, Sep 9, 2009 at 3:25 PM, <guox at ucalgary.ca>
wrote:
> I am wondering if you know how to return by function or show in boxplot,
> the indexes of unusual points, such as,
> points that are outside the box or in [Q3+1.5IQR,Max].
> For example,
>
>> boxplot(c(4,rnorm(20),8))
>
> There are 2 unusual points 4 and 8. How to show the indexes of 4 and 8 in
> the boxplot
> or return them by function?
>
> Thanks,
>
> -james
>
> ______________________________________________
> R-help at 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.
>


-- 
Jim Holtman
Cincinnati, OH
+1 513 646 9390

What is the problem that you are trying to solve?

Thank you very much.
But it seems that
x$out returns the values not the indexes of the  values (1,22).
-james
> boxplot returns a dataframe that has the values in it at "$out":
>
>> x <- boxplot(c(4,rnorm(20),8))
>> x
> $stats
>            [,1]
> [1,] -1.5364498
> [2,] -0.5282799
> [3,] -0.1398736
> [4,]  0.3065579
> [5,]  1.3430388
>
> $n
> [1] 22
>
> $conf
>            [,1]
> [1,] -0.4210947
> [2,]  0.1413474
>
> $out
> [1] 4 8
>
> $group
> [1] 1 1
>
> $names
> [1] "1"
>
>
>
> On Wed, Sep 9, 2009 at 3:25 PM, <guox at ucalgary.ca> wrote:
>> I am wondering if you know how to return by function or show in
>> boxplot,
>> the indexes of unusual points, such as,
>> points that are outside the box or in [Q3+1.5IQR,Max].
>> For example,
>>
>>> boxplot(c(4,rnorm(20),8))
>>
>> There are 2 unusual points 4 and 8. How to show the indexes of 4 and 8
>> in
>> the boxplot
>> or return them by function?
>>
>> Thanks,
>>
>> -james
>>
>> ______________________________________________
>> R-help at 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.
>>
>
>
>
> --
> Jim Holtman
> Cincinnati, OH
> +1 513 646 9390
>
> What is the problem that you are trying to solve?
>
>
>