all duplicated wanted
On Aug 3, 2012, at 09:06 , Weijia Wang wrote:
Hi, Has anyone been able to figure out how to print all duplicated observations? I have a dataset, with patients ID, and other lab records. Some patients have multiple lab records, but 'duplicated' ID will only show me the duplicates, not the original observation. How can I print both the original one and the duplicates?
Something like this? dd[ID %in% unique(ID[duplicated(ID)]),] Let's try:
ID <- sample(1:10, 10, replace=TRUE) table(ID)
ID 1 2 3 4 7 10 1 1 3 1 2 2
ID[ID %in% unique(ID[duplicated(ID)])]
[1] 7 7 10 3 3 3 10 The unique() bit is really just for efficiency:
ID[ID %in% ID[duplicated(ID)]]
[1] 7 7 10 3 3 3 10
Peter Dalgaard, Professor, Center for Statistics, Copenhagen Business School Solbjerg Plads 3, 2000 Frederiksberg, Denmark Phone: (+45)38153501 Email: pd.mes at cbs.dk Priv: PDalgd at gmail.com