Question

This is a double barrelled R question. I have a folder of data sets (in .csv) and they need to be altered before analysis. Each data set is a 1X10 matrix like:

1 2 3 4 5 6 7 8 9 10

and need to turn it into into the following 5X5 matrix inserting 1s on the diagonal:

1
1 1 
2 3 1
4 5 6 1
7 8 9 10 1

How can accomplish this transformation on multiple files in a folder?

Answer 1

Try this:

dir.in  <- "aaa"  # replace with your own input dir
dir.out <- "bbb"  # replace with your own output dir

files.in  <- list.files(dir.in, full.names = TRUE)
files.out <- file.path(dir.out, basename(files.in))

data.in <- lapply(files.in, scan, sep = ",")

mat.out <- lapply(data.in, function(x){ M <- diag(1, 5)
                                        M[upper.tri(M)] <- x
                                        t(M) })

mapply(write.csv, mat.out, files.out, col.names = FALSE, row.names = FALSE)