[R] How can I declare an empty zoo object?

[R. Michael Weylandt]

On Mon, Jul 30, 2012 at 11:18 PM, jpm miao <miaojpm at gmail.com> wrote:
> Hi,
>
>    I let xzoo be an empty  object:
>
>> xzoo<-{}

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?
>

For completeness,

xzoo <- zoo()

But like I said: don't do that.

Cheers,
Michael

>
>   Thanks,
>
>
> Miao
>
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>
>
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