[R] How can I declare an empty zoo object?
R. Michael Weylandt
michael.weylandt at gmail.com
Tue Jul 31 06:33:38 CEST 2012
On Mon, Jul 30, 2012 at 11:18 PM, jpm miao <miaojpm at gmail.com> wrote:
> I let xzoo be an empty object:
This sounds like the start of a bad idea....
> and I have an existing zoo object x1zoo_f. I would like to combine
> the two to make a new zoo object, and continue doing so in a loop,
> which is not shown here. However, when I type
>> xzoo<-cbind(xzoo, x1zoo_f)
Yep: the real answer is "don't do that." Since R is
copy-on-write+pass-by-reference and a few other nice things, this will
be painfully gut-wrenchingly paint-dryingly slow :-) Much better is to
make all your "x1zoo_f" objects and cbind them at once.
The perils of this idea and the appropriate fixings thereof have been
discussed here there and everywhere, but I think Pat Burn's
presentation in "the R Inferno" is the best (and certainly the most
fun) -- it's a worthwhile read and, perhaps an even higher compliment,
a worthwhile re-read.
Based on my rough memories of your recent posts, you won't understand
it all in the first pass (few do -- I certainly don't), but over time
you'll gain immensely from the work of one of R's wisest Virgils.
> An error message emerges
> Error in zoo(structure(x, dim = dim(x)), index(x), ...) :
> “x” : attempt to define invalid zoo object
> Is there any way to define an empty zoo object?
xzoo <- zoo()
But like I said: don't do that.
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