On Wed, Aug 25, 2010 at 7:43 AM, skan <juanp...@gmail.com> wrote:
> I have a zoo series. It lasts 10 years and its frequency is 15min.
>
> I'd like to get a new zoo series (or vector) with the same number of
> elements, whith each element equal to the first element of the day. That's,
> The first element everyday is repeated throughout the wole day.
>
> This is not same as aggregate(originalseries,as.Date,head,1) because this
> gives a vector with just one element for each day.
Try ave:
> library(zoo)
> library(chron)
> zz <- z <- zoo(1:100, chron(0:9/5))
> zz[] <- ave(coredata(z), as.Date(time(z)), FUN = function(x) head(x, 1))
> cbind(z, zz)
z zz
(01/01/70 00:00:00) 1 1
(01/01/70 04:48:00) 2 1
(01/01/70 09:36:00) 3 1
(01/01/70 14:24:00) 4 1
(01/01/70 19:12:00) 5 1
(01/02/70 00:00:00) 6 6
(01/02/70 04:48:00) 7 6
(01/02/70 09:36:00) 8 6
(01/02/70 14:24:00) 9 6
(01/02/70 19:12:00) 10 6
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