Hi Michael,

   1. I try this

        xzoo <- zoo()

       and it does work. OK, I will read the reference you provide to find
out why not to do so

    2. How can I create an array of zoo objects?

    3. Do you mean by "R's wisest virgil" Pat Burns' R Inferno?

To Arun:

    Even when indices (dates) of two zoo object don't match, I can cbind
them. It works for me!

    Thanks,

Miao



2012/7/31 R. Michael Weylandt <michael.weylandt@gmail.com>

> On Mon, Jul 30, 2012 at 11:18 PM, jpm miao <miaojpm@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
> >
> >         [[alternative HTML version deleted]]
> >
> >
> > ______________________________________________
> > 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.
> >
>

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