Hi Sam, On Mon, Nov 26, 2012 at 3:13 PM, Sam Steingold <[email protected]> wrote: > Hi, > >> * Steve Lianoglou <[email protected]> [2012-11-19 13:30:03 >> -0800]: >> >> For instance, if you want the min and max of `delay` within each group >> defined by `share.id`, and let's assume `infl` is a data.frame, you >> can do something like so: >> >> R> as.data.table(infl) >> R> setkey(infl, share.id) >> R> result <- infl[, list(min=min(delay), max=max(delay)), by="share.id"] > > perfect, thanks. > alas, the resulting table does not contain the share.id column. > do I need to add something like "id=unique(share.id)" to the list? > also, if there is a field in the original table infl which only depends > on share.id, how do I add this unique value to the summary? > it appears that "count=unique(country)" in list() does what I need, but > it slows down the process.
Hmm ... I think it should be there, but I'm having a hard time remember what you want. Could you please copy paste the output of `dput(head(infl, 20))` as well as an approximation of what the result is that you want. It will make it easier for us to talk more concretely about how to get what you want. -steve -- Steve Lianoglou Graduate Student: Computational Systems Biology | Memorial Sloan-Kettering Cancer Center | Weill Medical College of Cornell University Contact Info: http://cbio.mskcc.org/~lianos/contact ______________________________________________ [email protected] 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.
