R help - Oct 2006 - which duplicated rows to delete

Hi
Say I've this vector with several duplicates
>x<-c(1,2,3,4,2,6,2,8,2,3)
>which(duplicated(x))
[1] 5  7  9 10 11

But what I realy want is somthing like:
List({2,5,7}, {3,10}, ...)

Then from each sublist I can specify which of the duplicate items to drop

res<-NULL
for(vec in myDuplicateList) 
	res<-rbind(res, subset(data[vec,], myCrit))

I'll get some of the way by sorting my original data appropriately, as
it's
the second and following rows that are 'marked' as duplicates, but
that's
not quite enough

Hope for some hints
Kind regards S?ren

Hi

you can use

apply(outer(( (1:10)[1:10%in%x]), x, "=="), 1, which)

to get list of duplicates. But then you will need to specify which 
duplicates you want to discard which can be problematic.

HTH
Petr

On 30 Oct 2006 at 11:11, S?ren Merser wrote:

From:           	S?ren Merser <merser at image.dk>
To:             	"R - help" <r-help at stat.math.ethz.ch>
Date sent:      	Mon, 30 Oct 2006 11:11:01 +0100
Subject:        	[R] which duplicated rows to delete
> Hi
> Say I've this vector with several duplicates
> >x<-c(1,2,3,4,2,6,2,8,2,3)
> 
> >which(duplicated(x))
> [1] 5  7  9 10 11
> 
> But what I realy want is somthing like:
> List({2,5,7}, {3,10}, ...)
> 
> Then from each sublist I can specify which of the duplicate items to
> drop
> 
> res<-NULL
> for(vec in myDuplicateList) 
>  res<-rbind(res, subset(data[vec,], myCrit))
> 
> I'll get some of the way by sorting my original data appropriately, as
> it's the second and following rows that are 'marked' as
duplicates,
> but that's not quite enough
> 
> Hope for some hints
> Kind regards S?ren
> 
> ______________________________________________
> 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

Try this.  The first line breaks it up into lists and the second
line drops any list that is not greater than 1 in length:

out <- tapply(seq(x), x, function(x)x)
out[sapply(out, length) > 1]

On 10/30/06, S?ren Merser <merser at image.dk>
wrote:
> Hi
> Say I've this vector with several duplicates
> >x<-c(1,2,3,4,2,6,2,8,2,3)
>
> >which(duplicated(x))
> [1] 5  7  9 10 11
>
> But what I realy want is somthing like:
> List({2,5,7}, {3,10}, ...)
>
> Then from each sublist I can specify which of the duplicate items to drop
>
> res<-NULL
> for(vec in myDuplicateList)
>        res<-rbind(res, subset(data[vec,], myCrit))
>
> I'll get some of the way by sorting my original data appropriately, as
it's
> the second and following rows that are 'marked' as duplicates, but
that's
> not quite enough
>
> Hope for some hints
> Kind regards S?ren
>
> ______________________________________________
> 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.
>