Looping multiple dimensions
I would suggest that you use a 'list' for the data. Something like
this should work:
objs <- grep("^mrunoff_", ls(), values=TRUE) # get the names of the objects
result <- lapply(objs, function(.obj){
.obj <- get(.obj) # get the value
lapply(1:12, function(. iter) .obj[,, .iter])
})
On Fri, Jan 22, 2010 at 11:32 AM, Steve Murray <smurray444 at hotmail.com> wrote:
Dear all, I have 30 arrays, each with dimensions 720,360,12. The naming format for each of these 30 objects is: mrunoff_5221, mrunoff_5222... mrunoff_5250. For example:
str(mrunoff_5221)
? num [1:720, 1:360, 1:12] NA NA NA NA NA NA NA NA NA NA ...? (the initial NA's are nothing to worry about) I am looking for a way by which I can extract each of the third dimension of these grids (1:12) in turn, along with the first and second dimensions, to create new objects in the following style: #2071 mrunoff_207101 <- mrunoff_5221[,,1] mrunoff_207102 <- mrunoff_5221[,,2] mrunoff_207103 <- mrunoff_5221[,,3] mrunoff_207104 <- mrunoff_5221[,,4] mrunoff_207105 <- mrunoff_5221[,,5]?? ...(etc. - up to [,,12]) #2072 mrunoff_207201 <- mrunoff_5222[,,1] mrunoff_207202 <- mrunoff_5222[,,2] mrunoff_207203 <- mrunoff_5222[,,3] mrunoff_207204 <- mrunoff_5222[,,4] mrunoff_207205 <- mrunoff_5222[,,5]? ...(etc. - up to [,,12]) and mrunoff_ continues to 2100 and 5250 respectively. Clearly, this is a cumbersome and non-sustainable way to proceed! There will be 360 new objects in total, and I imagine that there must be a more effective way of achieving this, either via a loop or, possibly, one of the 'apply' functions. Yet my attempts to date have so far resulted in... well, a complete mess! If anyone has any suggestions as to a more efficient means of achieving this, then I'd be very grateful to hear them. Many thanks, Steve
_________________________________________________________________ Tell us your greatest, weirdest and funniest Hotmail stories ______________________________________________ R-help at r-project.org 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.
Jim Holtman Cincinnati, OH +1 513 646 9390 What is the problem that you are trying to solve?