Hi Ivo, On Mon, Oct 10, 2011 at 10:58 AM, ivo welch <ivo.we...@gmail.com> wrote: > hi steve---agreed...but is there any other computer language in which > an expression in a [ . ] is anything except a tensor index selector?
Sure, it's a type specifier in scala generics: http://www.scala-lang.org/node/113 Something similar to "scale-eez" in haskell. Aslo, MATLAB (ugh) it's not even a tensor selector (they use "normal" parens there). But I'm not sure what that has to do w/ the price of tea in china. With data.table, "[" still is "tensor-selector" like, though. You can just pass in another data.table to use as the "keys" to do your selection through the `i` argument (like "selecting rows"), which I guess will likely be your most common use case if you're moving to data.table (presumably you are trying to take advantage of its quickness over big-table-like objects. You can use the `j` param to further manipulate columns. If you pass in a data.table as `i`, it will add its columns to `j`. I'll grant you that it is different than your standard "rectangular object" selection in R, but the motivation isn't "so strange" as both i,j params in normal calls to 'xxx[i,j]' are for selecting (ok not manipulating) rows and columns on other "rectangular" like objects, too. -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 ______________________________________________ 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.
