Phil, Pre-allocation makes sense. However, I don't know the size of my resulting vector when starting. In my loop, I only pull off results that meet a certain threshold.
-N On 8/26/09 2:07 PM, Phil Spector wrote: > Noah - > I would strongly advise you to preallocate the result vector > using numeric() or rep(), and then enter the values based on > subscripts. Allowing objects to grow inside of loops is one of > the biggest mistakes an R programmer can make. > > - Phil Spector > Statistical Computing Facility > Department of Statistics > UC Berkeley > spec...@stat.berkeley.edu > > > On Wed, 26 Aug 2009, Noah Silverman wrote: > >> The actually process is REALLY complicate, I just gave a simple example >> for the list. >> >> I have a lot of steps to process the data before I get a final >> "score". (nested loops, conditional statements, etc.) >> >> Right now, I'm just printing the scores to the screen. I'd like to >> accumulate them in some kind of data structure so I can either write >> them to disk or graph them. >> >> -N >> >> On 8/26/09 12:27 PM, Erik Iverson wrote: >>> How about ?append, but R is vectorized, so why not just >>> >>> result_list<- 2*item^2 , or for more complicated tasks, the >>> apply/sapply/lapply/mapply family of functions? >>> >>> In general, the "for" loop construct can be avoided so you don't >>> have to think about messy indexing. What exactly are you trying to do? >>> >>> -----Original Message----- >>> From: r-help-boun...@r-project.org >>> [mailto:r-help-boun...@r-project.org] On Behalf Of Noah Silverman >>> Sent: Wednesday, August 26, 2009 2:20 PM >>> To: r help >>> Subject: [R] Managing output >>> >>> Hi, >>> >>> >>> Is there a way to build up a vector, item by item. In perl, we can >>> "push" an item onto an array. How can we can do this in R? >>> I have a loop that generates values as it goes. I want to end up >>> with a >>> vector of all the loop results. >>> >>> In perl it woud be: >>> >>> for(item in list){ >>> result<- 2*item^2 (Or whatever formula, this is just a pseudo >>> example) >>> Push(@result_list, result) (This is the step I can't do in R) >>> } >>> >>> >>> Thanks! >>> >>> ______________________________________________ >>> R-help@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. >>> >> >> [[alternative HTML version deleted]] >> >> ______________________________________________ >> R-help@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. >> [[alternative HTML version deleted]] ______________________________________________ R-help@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.
