The three was a typo, which I regret very much. I don't know why I didn't think of apply. I was obsessed with doing it as a table. Thanks for your response, -Andy
> -----Original Message----- > From: Tony Plate [mailto:[EMAIL PROTECTED] > Sent: Tuesday, April 26, 2005 2:00 PM > To: Andy Bunn > Cc: R-Help > Subject: Re: [R] Summarizing factor data in table? > > > Do you want to count the number of non-NA divisions and organizations in > the data for each year (where duplicates are counted as many times as > they appear)? > > > tapply(!is.na(foo$div), foo$yr, sum) > 1998 1999 2000 > 0 4 2 > > tapply(!is.na(foo$org), foo$yr, sum) > 1998 1999 2000 > 4 4 2 > > > > Or perhaps the number of unique non-NA divisions and organizations in > the data for each year? > > > tapply(foo$div, foo$yr, function(x) length(na.omit(unique(x)))) > 1998 1999 2000 > 0 4 2 > > tapply(foo$org, foo$yr, function(x) length(na.omit(unique(x)))) > 1998 1999 2000 > 4 4 2 > > > > (I don't understand where the "3" in your desired output comes from > though, which maybe indicates I completely misunderstand your request.) > > Andy Bunn wrote: > > I have a very simple query with regard to summarizing the > number of factors > > present in a certain snippet of a data frame. > > Given the following data frame: > > > > foo <- data.frame(yr = c(rep(1998,4), rep(1999,4), > rep(2000,2)), div = > > factor(c(rep(NA,4),"A","B","C","D","A","C")), > > org = factor(c(1:4,1:4,1,2))) > > > > I want to get two new variables. Object ndiv would give the number of > > divisions by year: > > 1998 0 > > 1999 3 > > 2000 2 > > Object norgs would give the number of organizations > > 1998 4 > > 1999 4 > > 2000 2 > > I figure xtabs should be able to do it, but I'm stuck without a > for loop. > > Any suggestions? -Andy > > > > ______________________________________________ > > [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 > > > > ______________________________________________ [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
