Re: [R] Using by() and stacking back sub-data frames to one data frame

One thing you might consider when working with large dataframes is that instead of partitioning the dataframe into smaller ones, create a list of indices and use that to access the subset. Works especially well when using 'lapply' to cromp through many segments of a data frame: y suid

Re: [R] Using by() and stacking back sub-data frames to one data frame

Have a look at ddply from the plyr package, http://had.co.nz/plyr. It's made for exactly this type of operation. Hadley On Wed, Jun 24, 2009 at 10:34 PM, Stephan Lindnerlindn...@umich.edu wrote: Dear all, I have a code where I subset a data frame to match entries within levels of an factor

Re: [R] Using by() and stacking back sub-data frames to one data frame

Your request for a more general approach is precisely the reason that Hadley Wickham wrote the plyr package. He describes a split-apply- combine strategy for a variety of data structures and tools to implement those strategies here: http://had.co.nz/plyr/plyr-intro-090510.pdf The argument

[R] Using by() and stacking back sub-data frames to one data frame

Dear all, I have a code where I subset a data frame to match entries within levels of an factor (actually, the full script uses three difference factors do do that). I'm very happy with the precision with which I can work with R, but since I loop over factor levels, and the data frame is big,

Re: [R] Using by() and stacking back sub-data frames to one data frame

try do.call(rbind, yourByList) hth, Kingsford Jones On Wed, Jun 24, 2009 at 9:34 PM, Stephan Lindnerlindn...@umich.edu wrote: Dear all, I have a code where I subset a data frame to match entries within levels of an factor (actually, the full script uses three difference factors do do