R help - Aug 2010 - Repeat the first day data through all the day. Zoo

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Hello

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.

cheers

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On Wed, Aug 25, 2010 at 7:43 AM, skan <juanpide at 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

On Wed, Aug 25, 2010 at 7:43 AM, skan <juanpide at gmail.com>
wrote:
>
> ?down vote ?favorite
>
>
> Hello
>
> 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.
>
> cheers
>
Here are a few more solutions too:

library(zoo)
library(chron)
z <- zoo(1:10, chron(0:9/5))

# aggregate / na.locf
z.ag <- aggregate(z, as.Date, head, 1)
na.locf(z.ag, xout = time(z))

# duplicated / na.locf
z.na <- ifelse.zoo(!duplicated(as.Date(time(z))), z, NA)
na.locf(z.na)

# ave - as before
zz <- z
zz[] <- ave(coredata(z), as.Date(time(z)), FUN = function(x) head(x, 1))
zz