I hadn't thought of that. I use the following at one point in my program tmp <- with(data, tapply(variable, index, table))
Which returns a list. So, I just went with it for the rest of my program. I'm changing code now to arrays, I think you're right and this may be a better representation. I need to walk through this and see what turns up. Thanks for the recommendation. > -----Original Message----- > From: Gabor Grothendieck [mailto:[EMAIL PROTECTED] > Sent: Wednesday, January 24, 2007 11:06 AM > To: Doran, Harold > Cc: r-help@stat.math.ethz.ch > Subject: Re: [R] Replace missing values in lapply > > I wonder if a list of matrices is the best representation? > Do your matrices all have the same dimension as in: > > TP <- list(matrix(c(1:3, NA), 2), matrix(c(NA, 1:3), 2)) > > # Then you could consider representing them as an array: > > TPa <- array(unlist(TP), c(2,2,2)) > > # in which case its just > > TPa[is.na(TPa)] <- 0 > TPa > > > On 1/24/07, Doran, Harold <[EMAIL PROTECTED]> wrote: > > I have some matrices stored as elements in a list that I am working > > with. On example is provided below as TP[[18]] > > > > > TP[[18]] > > level2 > > level1 1 2 3 4 > > 1 79 0 0 0 > > 2 0 0 0 0 > > 3 0 0 0 0 > > 4 0 0 0 0 > > > > Now, using prop.table on this gives > > > > > prop.table(TP[[18]],1) > > level2 > > level1 1 2 3 4 > > 1 1 0 0 0 > > 2 > > 3 > > 4 > > > > It is important for the zero's to retain their position as > this matrix > > will subsequently be used in some matrix multiplication and hence, > > must be of dimension 4 by 4 so that is it conformable for > > multiplcation with another matrix. > > > > In looking at the structure of the object resulting from > prop.table I > > see NaNs, and so I can do this > > > > > rr <- TP[[18]] > > > rr[is.na(rr)] <- 0 > > > rr > > level2 > > level1 1 2 3 4 > > 1 79 0 0 0 > > 2 0 0 0 0 > > 3 0 0 0 0 > > 4 0 0 0 0 > > > > This is exactly what I want for each matrix. But, I have multiple > > matrices stored within the list that need to be changed and so I am > > trying to resolve this via lapply, but something is awry > (namely the > > user), but I could use a little help. > > > > I was thinking the following function should work, but it > doesn't. It > > reduces each matrix within the list to a 0. > > > > PP <- lapply(TP, function(x) x[is.na(x)] <- 0) > > > > Am I missing something obvious? > > > > Harold > > > > > > [[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 > > and provide commented, minimal, self-contained, reproducible code. > > > ______________________________________________ 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 and provide commented, minimal, self-contained, reproducible code.