similar to: summary statistics for lists of matrices or dataframes

Dear all, I think that my question is very simple but I failed to solve it. I have a list which elements are matrices like this: >mylist [[1]] [,1] [,2] [,3] [1,] 1 3 5 [2,] 2 4 6 [[2]] [,1] [,2] [,3] [1,] 7 9 11 [2,] 8 10 12 I'd like to create a matrix M<-mylist[[1]]+mylist[[2]] [,1] [,2] [,3] [1,] 8 12 16 [2,] 10 14 18

Hi How do I make do.call() take "+" as a function for a list of more than two elements? Toy problem follows: f <- function(i){matrix((1:6)^i,2,3)} # Thus f() returns a matrix of size 2x3; I want to add a whole bunch of such matrices, # as in f(1) + f(2) + f(3) + f(4) # But: > do.call("+",sapply(1:4,f,simplify=FALSE)) Error in do.call("+",

Hi R, I have a list of matrices. I need to get the sum of all the matrices in the list. Example: a=b=c=d=matrix(1:4,2,2) l=list(a,b,c,d) I need: > a+b+c+d [,1] [,2] [1,] 4 12 [2,] 8 16 Something like do.call("+",l) is not working...why is this? I may not be knowing the number of matrices in the list... Thanks, Shubha This e-mail

R-devel, I'm in the process of choosing a name for a new package. I've already decided that the name will have two parts, 'portfolio' and 'sim', but can't decide between 'portfolioSim' and 'portfolio.sim'. Is there any good reason to choose one over the other? Thanks in advance, Jeff -- Jeff Enos Kane Capital Management jeff at kanecap.com

I have a pdf file that I would like to parse into R: http://www.williams.edu/Registrar/geninfo/faculty.pdf For now, I open the file in Acrobat by hand, then save it "as text" and then use readLines(). That works fine but a) I am concerned that some information may be lost and b) I may be doing this a lot, so I would rather have R grab the information from the pdf file directly. So: is

I know that there must be a cool way of doing this, but I can't think of it. Let's say I have an dataframe with NA's. > x <- data.frame(a = c(0,1,2,NA), b = c(0,NA,1,2), c = c(NA, 0, 1, 2)) > x a b c 1 0 0 NA 2 1 NA 0 3 2 1 1 4 NA 2 2 > I know it is easy to replace all the NA's with zeroes. > x[is.na(x)] <- 0 > x a b c 1 0 0 0 2 1 0 0 3 2 1

How reliable is R-Forge? http://r-forge.r-project.org/ It is down now (for me). Reporting "R-Forge Could Not Connect to Database: " I have just started to use it for a project. It has been down for several hours (at least) on different occasions over the last couple of days. Is that common? Will it be more stable soon? Apologies if this is not an appropriate question for R-help. Dave

How reliable is R-Forge? http://r-forge.r-project.org/ It is down now (for me). Reporting "R-Forge Could Not Connect to Database: " I have just started to use it for a project. It has been down for several hours (at least) on different occasions over the last couple of days. Is that common? Will it be more stable soon? Apologies if this is not an appropriate question for R-help. Dave

folks, if i have three matrices, a, b, cc with some colnames in common, and i want to create a matrix which consists of the common columns added up, and the other columns tacked on, what's a good way to do it? i've got the following roundabout code for two matrices, but if the number of matrices increases, then i'm a bit stymied. > a <- matrix(1:20,ncol=4); colnames(a) <-

After a question on R, Prof Brian Ripley writes: > However, you did not give your affiliation and I do not like giving free > consultancy to undisclosed commercial organizations. Please in future use > a proper signature block so that helpers are aware of your provenance. I have one question and one comment. Question: Are there specific standards about this for R mailing lists? I

R-devel, I'm interested in looking at some examples of existing R packages that rely heavily on S4 classes to get a feel for varying styles and package organization techniques. Could you recommend any packages that might serve as a good starting point? Thanks in advance, Jeff

R-devel, I'm interested in looking at some examples of existing R packages that rely heavily on S4 classes to get a feel for varying styles and package organization techniques. Could you recommend any packages that might serve as a good starting point? Thanks in advance, Jeff

Moodle (www.moodle.org) is an open source course management system, a competitor to Blackboard. I am writing several hundred R questions that will be used within the quiz module in Moodle. Unfortunately, Moodle does not have a built in question type for R. You can read about the different questions types in Moodle here:

Hi, I would like to read several datasets and would like to create a set (list? sequence?) of many empty dataframes. How could this be done? How could I declare a set (list? sequence?) of many empty matrices? Thanks, Miao [[alternative HTML version deleted]]

Hi, In 1.4.1, I was able to create extra "empty" rows in a dataframe as so: > x <- data.frame(a = letters[1:3], b = 1:3) > x a b 1 a 1 2 b 2 3 c 3 > x[4,] a b NA NA NA > rbind(x, x[4,]) a b 1 a 1 2 b 2 3 c 3 NA NA NA > R.version _ platform sparc-sun-solaris2.6 arch sparc os solaris2.6

Hi, I am teaching a one month class in applied statistics and want to bring my students up to speed in R without devoting much/any lecture time to R instruction. I think that the best way to do this is to provide them with a lot of R questions for homework. These questions would be numerous (there is a lot of material to cover), go from very simple to somewhat complex, and focus on all the

Hello, Is this a bug or a feature? I am using R 2.7.1 on Apple OS X. > y <- matrix(1:3,nrow=3) # y is a single-column matrix > df <-data.frame(x=1:3,y=y) > sapply(df,data.class) x y "numeric" "numeric" > df$yy <- y > sapply(df,data.class) x y yy "numeric" "numeric" "matrix"

I am tying myself in knots over subscripts when applied to lists I have a list along the lines of: lis<-list(c("a","b","next","want1","c"),c("d", "next", "want2", "a")) >From which I want to extract the values following "next" in each member of the list, i.e. something along the lines of

R users, This probably involves a simple incantation of one of the flavors of apply... that I can't yet figure out. Consider a list of data frames. I'd like to apply a function (mean) across the list and return a dataframe of the same dimensions where each cell represents the mean of that cell across all dataframes. # set up the list x <- vector("list",2) names(x) <-

Hi, this is probably the easiest thing to do but I manage not finding the answer: I have a list with matrices of exact same format and headers. Now I would like to transform the list into an normal array. What is the proper way to do this? as.array changes the entire format and right now I only found the method of creating a new array, going through the entire list and copy the matrix in each