R help - Jan 2007 - rank function and NA in 2.3.1

Hi.

I am using R 2.3.1 on WIndows XP, and I am having trouble with the rank 
function in the presence of numerical NA data.  I want the NA's all to get 
the same rank, but they don't.  Here is an example from my session:

>ct_align_rets_f2$liq[6851:6859]
[1] 115396     NA 362595     NA 242986 340805     NA 692905
251533
>rankl=rank(ct_align_rets_f2$liq,na.last=FALSE,ties.method="min")
>rankl[6851:6859]
[1] 4392 2424 5535 2425 5037 5451 2426 6625 5082


What am I doing wrong?  Is there a way to check whether there's a problem 
with the data, i.e., somehow the NA's have different values?  (By the way, I
have tried not using na.last, and also different ties.methods, but the NA 
ranks have never come out equal.)

Thanks!


--  TMK  --
212-460-5430	home
917-656-5351	cell

Hi

one workaround could be to change your NA values to some number and 
do the rank with average, min or max option.
> x<-1:12
> x[c(5,10)]<-NA
> rank(x)
 [1]  1  2  3  4 11  5  6  7  8 12  9 10
> rank(x, ties="average")
 [1]  1  2  3  4 11  5  6  7  8 12  9 10
> x[which(is.na(x))]<-999
> rank(x, ties="average")
 [1]  1.0  2.0  3.0  4.0 11.5  5.0  6.0  7.0  8.0 11.5  9.0 10.0

Or you can go through rank source code and to change it so as it will 
behave as you wish.

HTH
Petr


On 11 Jan 2007 at 18:29, Talbot Katz wrote:

From:           	"Talbot Katz" <topkatz at msn.com>
To:             	r-help at stat.math.ethz.ch
Date sent:      	Thu, 11 Jan 2007 18:29:16 -0500
Subject:        	[R] rank function and NA in 2.3.1
> Hi.
> 
> I am using R 2.3.1 on WIndows XP, and I am having trouble with the
> rank function in the presence of numerical NA data.  I want the NA's
> all to get the same rank, but they don't.  Here is an example from my
> session:
> 
> 
> >ct_align_rets_f2$liq[6851:6859]
> [1] 115396     NA 362595     NA 242986 340805     NA 692905 251533
>
>rankl=rank(ct_align_rets_f2$liq,na.last=FALSE,ties.method="min")
> >rankl[6851:6859] [1] 4392 2424 5535 2425 5037 5451 2426 6625 5082
> 
> 
> What am I doing wrong?  Is there a way to check whether there's a
> problem with the data, i.e., somehow the NA's have different values? 
> (By the way, I have tried not using na.last, and also different
> ties.methods, but the NA ranks have never come out equal.)
> 
> Thanks!
> 
> 
> --  TMK  --
> 212-460-5430	home
> 917-656-5351	cell
> 
> ______________________________________________
> R-help at stat.math.ethz.ch 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.
Petr Pikal
petr.pikal at precheza.cz