S+ does allow duplicates in the row names if you ask for them to be allowed (with data.frame(..., dup.row.names=TRUE) or attr(df, "dup.row.names") <- TRUE).
They were allowed because bootstrappers were sampling the rows of data.frames with replacement and it turned out that a fair bit of time was being used calling make.unique() on the row names of the sample. There may be better solutions to that problem, but that is why S+ allows them. Bill Dunlap Spotfire, TIBCO Software wdunlap tibco.com > -----Original Message----- > From: [email protected] [mailto:[email protected]] On > Behalf Of Ajay Askoolum > Sent: Monday, March 05, 2012 11:42 PM > To: R General Forum > Subject: [R] Why aren't row names in a data frame unique? > > I expected the row names to be unique but a data frame appears to be able to > hold duplicate row names. > This makes me thing that there must be circumstances when it is necessary. > However, I cannot think of > any. Please enlighten me. > > [[alternative HTML version deleted]] > > ______________________________________________ > [email protected] 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. ______________________________________________ [email protected] 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.
