Duncan, Thank you so much. It is exactly what I was looking for. However, for some reason, indices() does not work ("Error: could not find function "indices"). I used which(), it worked.
Thanks again for the help, Julia Duncan Murdoch-2 wrote: > > On 08/10/2008 2:36 PM, liujb wrote: >> Dear R users, >> >> I have this vector that consists numeric numbers. Is there a command that >> detects the repeated numbers in a vector and returns the index of the >> repeated numbers (or the actual numbers)? For example, v <- c(3,4,5,7,4). >> The command would return me index 2 and 5 (or the repeated number, 4). > > duplicated() comes close, but the first occurence doesn't count as a > duplication: > > > duplicated(v) > [1] FALSE FALSE FALSE FALSE TRUE > > To convert into values, you can index v by it: > > > v[duplicated(v)] > [1] 4 > > and to find which indices are duplicated, > > > indices <- seq_along(v) > > indices[duplicated(v)] > [1] 5 > > If you really want to include the the first one, you can do something > like: > > > indices[ v %in% v[duplicated(v)] ] > [1] 2 5 > > > Duncan Murdoch > > ______________________________________________ > R-help@r-project.org 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. > > -- View this message in context: http://www.nabble.com/detect-repeated-number-in-a-vector-tp19884768p19887359.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ R-help@r-project.org 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.