Laetitia Marisa <[EMAIL PROTECTED]> writes: > Hello, > > Is there a simple and fast function that returns a vector of the number > of replications for each object of a vector ? > For example : > I have a vector of IDs : > ids <- c( "ID1", "ID2", "ID2", "ID3", "ID3","ID3", "ID5") > > I want the function returns the following vector where each term is the > number of replicates for the given id : > c( 1, 2, 2, 3,3,3,1 ) > > Of course I have a vector of more than 40 000 ID and the function I > wrote (it orders my data and checks on ID:Name of the data if the next > term is the same as the previous one (see below) ) is really slow > (30minutes for 44290 terms). But I don't have time by now to write a C > function. > Thanks a lot for your help,
Will this do it? > table(ids)[ids] ids ID1 ID2 ID2 ID3 ID3 ID3 ID5 1 2 2 3 3 3 1 Or (could be faster): > f <- factor(ids,levels=unique(ids)) > as.vector(table(f))[f] [1] 1 2 2 3 3 3 1 -- O__ ---- Peter Dalgaard Øster Farimagsgade 5, Entr.B c/ /'_ --- Dept. of Biostatistics PO Box 2099, 1014 Cph. K (*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918 ~~~~~~~~~~ - ([EMAIL PROTECTED]) FAX: (+45) 35327907 ______________________________________________ [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
