RE: [R] extract rows in dataframe with duplicated column values

From: Liaw, Andy <andy_liaw_at_merck.com>
Date: Fri 18 Mar 2005 - 14:25:01 EST


OK, strike one...

Here's my second try:

> cnt <- table(x[,1])
> v <- as.numeric(names(cnt[cnt > 1]))
> v

[1] 2 3
> x[x[,1] %in% v, ]

  a b
2 2 10
3 2 10
4 3 10
5 3 10
6 3 10

Andy

> From: Liaw, Andy
>
> Does this work for you?
>
> > x[table(x[,1]) > 1,]
> a b
> 2 2 10
> 3 2 10
> 5 3 10
> 6 3 10
>
> Andy
>
> > From: Tiago R Magalhaes
> >
> > Hi
> >
> > I want to extract all the rows in a data frame that have duplicates
> > for a given column.
> > I would expect this question to come up pretty often but I have
> > researched the archives and surprisingly couldn't find anything.
> > The best I can come up with is:
> >
> > x <- data.frame(a=c(1,2,2,3,3,3), b=10)
> > xdup1 <- duplicated(x[,1])
> > xdup2 <- duplicated(x[,1][nrow(x):1])[nrow(x):1]
> > xAllDups <- x[(xdup1+xdup2)!=0,]
> >
> > This seems to work, but it's so convoluted that I'm sure there's a
> > better method.
> > Thanks for any help and enlightenment
> > [[alternative HTML version deleted]]
> >
> > ______________________________________________
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>
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R-help@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 Received on Fri Mar 18 14:29:25 2005

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