On Tue, Feb 17, 2009 at 10:00:40AM -0600, Marc Schwartz wrote: > on 02/17/2009 09:06 AM Hans Ekbrand wrote: > > Hi r-help! > > > > Consider the following data-frame: > > > > var1 var2 var3 > > 1 3 1 4 > > 2 2 2 3 > > 3 2 2 3 > > 4 4 4 NA > > 5 4 3 5 > > 6 2 2 3 > > 7 3 4 3 > > > > How can I get R to convert this into the following? > > > > Value 1 2 3 4 5 > > var1 0 3 2 2 0 > > var2 1 3 1 2 0 > > var3 0 0 4 1 1 > > > > t(sapply(DF, function(x) table(factor(x, levels = 1:5)))) > 1 2 3 4 5 > var1 0 3 2 2 0 > var2 1 3 1 2 0 > var3 0 0 4 1 1 > > > The key is to turn each column into a factor with explicitly defined > common levels for tabulation. This enables the table result to have a > consistent format across each column, allowing for a matrix to be > created, rather than a list.
Thanks alot, Marc. Neat and efficient, just what I wanted.
BTW, before I saw that you actually included code, I tried on my own,
and wrote this:
my.count <- function(data.frame, levels) {
result.df <- data.frame(matrix(nrow=length(data.frame),ncol=levels))
for (i in 1:length(data.frame)) {
result.df[i,] <- table(factor(data.frame[[i]], levels = c(1:levels)))
}
result.df
}
which produces the same result. I take this to be a an instructive
example of unnecessary use of for-loops in R.
--
Hans Ekbrand (http://sociologi.cjb.net) <h...@sociologi.cjb.net>
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