Thanks very much to Achim Zeileis, Matt Weiner, and Andy Liaw for their solution. Declaring preferences as a "factor" worked!
Best, 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: [EMAIL PROTECTED] -------------------------------------------------------------------------- > -----Original Message----- > From: Achim Zeileis [mailto:[EMAIL PROTECTED] > Sent: Wednesday, April 20, 2005 12:13 PM > To: Ravi Varadhan > Cc: r-help@stat.math.ethz.ch > Subject: Re: [R] Keeping factors with zero occurrences in "table" output > > On Wed, 20 Apr 2005 11:38:13 -0400 Ravi Varadhan wrote: > > > 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? > > I think the cleanest way is to store the preferences as a "factor" and > tell R at the creation of that factor what the levels are, i.e. > preference <- factor(preference, levels = 1:7) > Then calling > table(preference) > will also report categories with 0 observations. > Z > > > > > > > > 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