Use of substitute -- was More powerful than objects() or ls()
According to Prof Brian D Ripley: |>
|> On Mon, 26 Mar 2001, Patrick Connolly wrote:
|> ..... |> > I think it would be simple enough if I could get something in R to |> > work the way substitute() does in Splus. The thinking seems to be |> > very different between the two dialects. Maybe if I tinker a bit |> > longer, I'll get the connexion between them. |> |> They are almost the same. (See V&R's `S Programming' for a detailed |> comparison.) There is a difference when using function arguments: |> S uses the initial values, R the current ones, so in R one often needs to |> substitute early or take care to work on copies. Indeed, V&R explains it, so that's useful. Thanks again, Brian. But as Thomas Lumley anticipated, it is not straighforward to make use of comment with it. Writing to and sourcing from a temporary text file is not very elegant, but also not very complicated, |> Ah, I think most of us keep our functions in files not in objects, even in |> S-PLUS. I even keep my datasets in files (or databases). I know John |> Chambers advocates an `S object is master' view in the Green book, but I |> don't find it very practical given current tools. It is very practical with my Splus function (even though I could write it rather a lot better now). It's useful on those occasions when I attach to a directory where I did similar work some years ago and look through the lists, functions, matrices, dataframes and the like that I used there. I can quickly decide what I can use in the present directory. Even so, there is good reason to have a file of the code the function uses, and now I know how to use substitute, that's easy to automate. |> A CVS archive of R/S code is a very useful way of version control. Sounds interesting. Where will I find information about CVS archives? V&R don't have any mention in the index/es. best
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