Re: [R] Competing with SPSS and SAS: improving code that loops through rows (data manipulation)

2010-03-27 Thread hadley wickham
> # Set up the ratio variables > system.time({ > temp <- cbind(data, do.call(cbind, lapply(names(data)[3:4], function(.x) >        { >                unlist(by(data, data$group, function(.y) .y[,.x] / > max(.y[,.x]))) >        }))) > colnames(temp)[5:6] <- paste(colnames(data)[3:4], 'ind.to.max',

Re: [R] Competing with SPSS and SAS: improving code that loops through rows (data manipulation)

2010-03-27 Thread Dimitri Liakhovitski
Dear all, thank you so much for your advice, and special thanks to you, Jim, for digging into my code (which was too long). I'll dig into yours now - it definitely looks very fast - and it's a lot of great learning for me. Because you can see - I am just a rudimentary programmer. Thank you very-ver

Re: [R] Competing with SPSS and SAS: improving code that loops through rows (data manipulation)

2010-03-27 Thread Jim Price
Here's my first stab. It removes some of the typical redundencies in your code (loops, building data frames by adding one column at a time) and instead does what is probably more canonical R style (although I'm willing to be corrected, as I suspect my code is a little suspect at times). For this

[R] Competing with SPSS and SAS: improving code that loops through rows (data manipulation)

2010-03-26 Thread Dimitri Liakhovitski
Dear R-ers, In my question there are no statistics involved - it's all about data manipulation in R. I am trying to write a code that should replace what's currently being done in SAS and SPSS. Or, at least, I am trying to show to my colleagues R is not much worse than SAS/SPSS for the task at han