Hi Tal,
Here's a way of doing the first bit...
assign2 <- function(x, ...) {
xname <- deparse(substitute(x))
assign(xname, ...)
x <- get(xname)
attr(x, "creation.time") <- Sys.time()
assign(xname, x, pos=.GlobalEnv)
}
Michael
On 11 November 2010 20:37, Tal Galili <tal.gal...@gmail.com> wrote:
> My objective is to start having meta-data on objects that I create.
> For example, consider the following function:
>
> assign2 <- function(x, ...)
> {
> assign("x", ...)
> attr(x, "creation time") <- Sys.time()
> x <<- x
> }
>
> assign2("x", 1:4)
>
> "assign2" assigns to x the vector 1:4, and it then also adds the creation
> time of the object.
>
> (Hat tip goes to Peter Alspach for pointing me to the concept of adding meta
> data to an object using attr)
>
>
> But this function has several major limitations:
> 1) It will not work for any assignment other then "x". For example
> assign2("y", 1:4)
> Doesn't work.
> How might this be fixed ?
> 2) This function will probably need to also search the parent environment if
> the variable already exists. If it does, then there should be a "update
> date" instead of "creation date". But for that to work, I'll need a
> solution for problem 1.
> 3) How will this handle a case when we are updating only a subset of the
> items? (for example: assign2("x[1:2]", 8:9) )
> 4) My real intention is to somehow change the "<-" operator (not simply the
> assign). I am unsure as to how to do that.
> 5) Are there any major pros/cons to the adding of such meta-data to objects?
> (for example, excessive overhead on memory/performance)
> 6) Is there already some system that knows how to do this in R (which I am
> simply ignorant about)?
>
> Thanks for following through, and for any suggestions/thoughts you might
> have.
>
> Best,
> Tal
>
>
>
>
>
> ----------------Contact
> Details:-------------------------------------------------------
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