On Monday, November 26, 2012, Sam Steingold wrote:
[snip]

>
> there is precisely one country for each id.
> i.e., unique(country) is the same as country[1].
> thanks a lot for the suggestion!
>
> > R> result <- f[, list(min=min(delay), max=max(delay),
> > count=.N,country=country[1L]), by="share.id"]


And is it performant?

It just occurred to me that this is even better:

R> setkeyv(f, c("share.id", "delay"))
R> result <- f[,  list(min=delay[1L], max=delay[.N], count=.N,
country=country[1L]), by="share.id"]



> --
> Sam Steingold (http://sds.podval.org/) on Ubuntu 12.04 (precise) X
> 11.0.11103000
> http://www.childpsy.net/ http://thereligionofpeace.com http://pmw.org.il
> http://honestreporting.com http://americancensorship.org
> Why do you never call me back after I scream that I will never talk to you
> again?!
>


-- 
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

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