Ravi -- If you use table on a factor, you'll get 0's if appropriate:
> table(sample(1:5, 10, replace = TRUE)) #no 2's, by chance 1 3 4 5 3 1 2 4 > table(sample(1:5, 20, replace = TRUE)) # no 6's here, so 6 doesn't show up 1 2 3 4 5 3 5 2 5 5 ## now make it a factor, and you get 0 3's and 0 6's > table(factor(sample(1:5, 20, replace = TRUE), levels = 1:6)) 1 2 3 4 5 6 5 4 0 1 10 0 ## just happened to get no 3's in previous sample; it doesn't happen every time: > table(factor(sample(1:5, 20, replace = TRUE), levels = 1:6)) 1 2 3 4 5 6 7 3 3 5 2 0 You can probably create the factor you want with "interaction" on participants and ranks. Hope this helps, Matt Wiener -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Ravi Varadhan Sent: Wednesday, April 20, 2005 11:38 AM To: r-help@stat.math.ethz.ch Subject: [R] Keeping factors with zero occurrences in "table" output Dear R group, I have a data frame which contains data on preferences on 7 items (ranks 1 through 7) listed by each participant. I would like to tabulate this in a 7x7 table where the rows would be the items and the columns would be the number of times that item received a particular rank. I tried doing this by creating a matrix by "rbind"ing each vector obtained using "table" on each item. This, however, does not work because there are some items which didn't receive some of the ranks, so "table" does not list that item. Is there a way to force it to list the item and give a "0" to it? Or, is there a simpler way to solve this problem? Thanks for any help, Ravi. -------------------------------------------------------------------------- Ravi Varadhan, Ph.D. Assistant Professor, The Center on Aging and Health Division of Geriatric Medicine and Gerontology Johns Hopkins University Ph: (410) 502-2619 Fax: (410) 614-9625 Email: <mailto:[EMAIL PROTECTED]> [EMAIL PROTECTED] -------------------------------------------------------------------------- [[alternative HTML version deleted]] ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
