similar to: Optional variables in function?

I apologize for what may be a newbie question: I have two sets of data, one is X,Y,Z data that I'd like to make a contour plot of (Z defining the contours), and a second set of X,Y data (Y as a function of X) which I would like made into a line plot OVERLAYED on the contour plot (X and Y from both plots are in the same units and will have overlapping values). Any suggestions on how to do this

If I want to do a join based on *two* matching fields in two data frames, can merge() handle this? It appears to only handle a single matching column -- do I need to make a "metacolumn" or is there some way to do this? E.g.: Dataframe 1 contains columns A,B,C and Dataframe 2 contains A,B,D I want an output A,B,C,D which places C and D together if A and B match (otherwise, make two

I'm getting a weird behavior using R 2.5.0 for MacOS X -- I have a csv file with a "properly formatted" date/time field, e.g. After reading in the csv to "hourly_met_data", with a "date" field hourly_met_data$date <- as.POSIXct(hourly_met_data$date) works exactly as it is supposed to (e.g. Min/max of that field are calculated correctly). However, when I

Hi there, couple of questions on data frames: 1) Is there a way to build an empty data frame, containing nothing but the data frame variable names? 2) Is there a way to reorder the variables in a data frame, e.g. When I go to write out a data frame using write.table or write.matrix, I want the output in a certain order... 3) How to I "append" to the bottom of a dataframe? Thanks! --j

Besides the primary citation, "Kennedy, W. J. Jr and Gentle, J. E. (1980) Statistical Computing Marcel Dekker." (which is $300 and my library doesn't have it), is there any other documentation on how to take a poly() object and predict "by hand" new data? E.g. What do those coefficients actually mean ("The orthogonal polynomial is summarized by the coefficients, which

I'm getting the following error: > headerinfo=readLines(met_station_file,n=8) > headerinfo [1] "Plot Title: tahoe met validation ,,,,,,," [2]Error: invalid multibyte string met_station_file's first 8 lines are as follows: Plot Title: tahoe met validation ,,,,,,, #,"Time, GMT-07:00","Temp, ?F",Coupler Attached,Host Connected,Coupler

I have 2GB installed on my windows XP box running R 1.9.0, and after performing a prune.tree(intree,newdata), I get an out of memory error within R, but it says the maximum allowed is 1024gb (1/2 of what I have!) Can R not use more than 1GB on an XP box? I noticed I had ~600mb left over after R conked out, so clearly I had more memory... What about virtual memory? --j -- Jonathan Greenberg

R-developers: I'm working on updating my R package "spatial.tools", and one thing I was wondering was the proper way to have hidden functions -- should I simply not export them to the namespace and use the ::: operator to call them (which is what I currently do)? --j -- Jonathan A. Greenberg, PhD Assistant Professor Global Environmental Analysis and Remote Sensing (GEARS)

I have a binary file which is an image with multiple bands, arranged in BSQ format such that R, B and G are all N x M sized matrices (corresponding to Red, Blue and Green colors respectively). The BSQ file arranges the data as [R, B, G], so to access the B matrix, I have to read forward N x M + 1 number of samples. Is there a fast way to define a variable as the B matrix exclusively (e.g. Can I

Quantreggers: I'm trying to run rq() on a dataset I posted at: https://docs.google.com/file/d/0B8Kij67bij_ASUpfcmJ4LTFEUUk/edit?usp=sharing (it's a 1500kb csv file named "singular.csv") and am getting the following error: mydata <- read.csv("singular.csv") fit_spl <- rq(raw_data[,1] ~ bs(raw_data[,i],df=15),tau=1) > Error in rq.fit.br(x, y, tau = tau, ...) :

R-helpers: What would be the absolute fastest way to make a large "empty" file (e.g. filled with all zeroes) on disk, given a byte size and a given number number of empty values. I know I can use writeBin, but the "object" in this case may be far too large to store in main memory. I'm asking because I'm going to use this file in conjunction with mmap to do parallel

This is probably a very noobish question, but if I want to create a function that allows an undetermined number of, say, numeric vectors to be fed to it, I would use: myfunction = function(...) { # Do something } Right? If so, how do I a) count the number of vectors "fed" to the function, and b) how do I treat those vectors as variables, e.g. for the call:

R-helpers: It looks like http://finzi.psych.upenn.edu/search.html has stopped spidering the mailing lists -- this used to be my go-to site for searching for R solutions. Are there any good replacements for this? I want to be able to search both functions and mailing lists at the same time. Cheers! --j -- Jonathan A. Greenberg, PhD Assistant Professor Department of Geography University of

R-helpers: I need a quick help with the following graph (I'm a lattice newbie): require("lattice") npp=1:5 names(npp)=c("A","B","C","D","E") barchart(npp,origin=0,box.width=1) # What I want to do, is add a single vertical line positioned at x = 2 that lays over the bars (say, using a dotted line). How do I go about doing this?

I was hoping I could get some help with an import question. I work with remote sensing imagery which commonly comes in binary form in various interleaving formats (byte interleaved by line, by pixel, etc..). These files are 2d spatial x B bands in size, and I want to be able to extract the band values from various pixels (so each line of data into R would be one pixel x B bands). What's the

R-helpers: Say I have a list: myvariables <- list(a=1:10,b=20) Is there a way to load the list components into the environment as variables based on the component names? i.e. by applying this theoretical function to myvariables I would have the variables a and b loaded into the environment without having to explicitly define them. --j -- Jonathan A. Greenberg, PhD Assistant Professor

R-helpers: I'm running a file search on my entire drive (Mac OS X) using: files_found <- list.files(dir="/",pattern=somepattern,recursive=TRUE,full.names=TRUE) where somepattern is a search pattern (which I have confirmed via a unix "find / -name somepattern" only returns ~ 3 results). I keep getting an error: Error: C stack usage is too close to the limit when

R-helpers: I'd like to be able to store all the file information from an ftp site (e.g. file and foldernames) through an R command. Any ideas how to do this? Here's an example site to use: ftp://e4ftl01.cr.usgs.gov/MOTA/MCD15A3.005 --j -- Jonathan A. Greenberg, PhD Assistant Professor Department of Geography and Geographic Information Science University of Illinois at

R-developers: I'm beginning to work on a manuscript for a set of functions I developed for a package I have on CRAN (spatial.tools), and I'd like to rename a function in my package to give a better idea of what it does prior to manuscript submission -- is there a "safe" way to do a backwards-compatible rename of a function within a CRAN package (so functions that rely on the

R-developers: I had a quick question for the group -- let's say a package I am developing depends on a single, small function from a large CRAN-listed package. I can, of course, set a dependency within my own package, but are there means by which I can include the R script + man file DIRECTLY in my package (of course attributing the code to the original programmer). Does it require me