table(match(x, x)) gives you the numbers but the labels are a bit more work.
E.g., I'll define another list > x <- list(c("1", "2", "4"), c("1", "2", "4"), 2^(0:4), 3^(1:2), 2^(0:4)) > tb <- table(m <- match(x, x)) > m [1] 1 1 3 4 3 > tb 1 3 4 2 2 1 which says that the first element of x is seen twice, the third twice, and the fourth once. How to organize that the best depends on what you want to do with the data. Bill Dunlap Spotfire, TIBCO Software wdunlap tibco.com > -----Original Message----- > From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On > Behalf Of zhenjiang xu > Sent: Wednesday, August 31, 2011 9:25 AM > To: r-help > Subject: [R] counting the duplicates in an object of list > > Hi all, > > I have a list x: > > > x=list(a=c('1','2'),b=c('2','3'),c=c('1','2'),d=c('2','3')) > > I can get the unique elements with unique(), but how can I get the > number of duplicates for each unique elements? > > > unique(x) > [[1]] > [1] "1" "2" > > [[2]] > [1] "2" "3" > > Thanks > > -- > Best, > Zhenjiang > > ______________________________________________ > 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. ______________________________________________ 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.