I have a lot of java data analysis code I have written for processing 400MB per day of compressed packet sniffer data. I have been playing with R recently and struggling to understand where the dividing line between languages like java and R is in terms of which sorts of code in makes sense to write in each. It struck me the other day, as I was using excel to manually manipulate large tables of string and numeric data doing things like table lookup (using excel's vlookup function) and partitioning a table by the unique values of a text column to perform sums on different numeric columns within the partitions (you wouldn't believe the tricks I have stumbled upon to make excel do things like that over the years) that R seemed to be made for computations like this. Once that occured to me, I opened "An Introduction to R" again and saw how easy R's index arrays, match(), and tapply() functions make all of those operations. I don't know how obvious that must seem to most of the people on this list, but I thought I'd offer it up in case anyone else found it to be the key to unlocking R that I have found it to be. Thank you, R authors and contributers, for such a fantastic tool. I absolutely recoiled in horror after cracking a book on Visual Basic for Excel in one of my previous attempts to automate the manual stuff I have been doing in excel these past few years. It is so nice to have a system like R to turn to for this. Chris Marshall -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-help-request at stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._