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I'm just getting started with R, so feel free to point me to the appropriate documentation if this is already answered somewhere (though I've been unable to find it myself). This does seem like a rather basic question. I want to fold a table into a matrix. The table is formatted like so: Column_Index Value 1 486 2 688 3 447 4 555 5

I have a data frame with three columns, x, y, and a. I want to create a matrix from these values such that for matrix m: m[x,y] == a Obviously, I can go row by row through the data frame and insert the value a at the correct x,y location in the matrix. I can make that slightly more efficient (perhaps), by doing something like this: > for (each.x in unique(df$x)) m[each.x, df$y[df$x ==

I'm currently using the below function from some library (MASS?) for writing my data out to file. I'm using it instead of plain old "write" because it does buffering. The problem that I'm having is that the numbers are space padded, but I need true tab-delineated files. It looks like the spaces are coming from 'format', but I don't see an option for format to

For those of you who are using the latest version of the BBEdit text editor, I have put together a language definition file for R so that you can get nice syntax coloring. It is available at http://smalltime.com/gene/R.plist Copy the file into "~/Library/Application Support/BBEdit/Language Modules/" and restart BBEdit. Make sure to switch the mapping of ".r" files from

I'm sure there must be various peak-finding algorithms out there. Not knowing of any, I have written one myself*, but I thought I'd ask to see what's out there. Basically, I have a 2-dimensional data set and I want to identify local peaks in the data, while ignoring "trivial" peaks. My naive algorithm first identifies every peak and valley (point of inflection change