review of duplicate values handling

[Stafford Phillip-APS095 <phillip.stafford@motorola.com>]

Thanks to all who responded to the question of how to get ALL duplicated 
elements instead of the subsequent ones, as usual there are some great general 
methods summarized here:

Bert Gunter reminded me of how powerful is.element and match() are:
is.element(x,x[duplicated(x)])


Tom Jagger provided a function that gives you all duplicated elements:

all.dup <- function(x)
           {
               dups<-duplicated(x) 
               return( is.element( x, unique(x[duplicated(x)]) ) ) 
             }

Tim Hesterberg:  making non-unique row names is pretty handy, the key is:
data.frame(..., row.names=row.names(...),dup.row.names=T)       (this is worth 
the price of admission alone)


Bert, Tim, Myong-Hee Sung all suggested:
is.element(x, duplicated(x))


Thanks to all who responded, it's been a great present.


Sincerely;

Phillip