R help - Apr 2011 - Removing not duplicated rows

Hello R users,

I have a problem to delete rows in a table which are not duplicated in order
of an id number

a short example:

x <- data.frame(cbind(id=c(1,2,2,2,3,3,4,5,6,6), value=1:10))

x_new <- x[which(duplicated(x$id)),]
> x_new
   id value
3   2     3
4   2     4
6   3     6
10  6    10

The problem is that my command not only delet the id number which occur only
one time.
Also the first row with the id number (2,3 and 6 is deleted).

Thanks!

With best regards

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As I understand it, you are trying to subset the data frame to include only 
rows with a non-unique id.

Try this:
x <- data.frame(cbind(id=c(1,2,2,2,3,3,4,5,6,6), value=1:10))
id.table <- table(x$id)
x_new <- subset(x, id %in% id.table[id.table > 1])

Jeremy

Sorry, I left out the names() function in the last step.

Try this instead:
x <- data.frame(cbind(id=c(1,2,2,2,3,3,4,5,6,6), value=1:10))
id.table <- table(x$id)
x_new <- subset(x, id %in% names(id.table[id.table > 1]))

Jeremy