R help - Jan 2011 - Semi-Regular Time Series with Missing Values

Hi,

I'm trying to make a ts object that has both NA values and a frequency other
than 1 (so I can use stl). I've tried all permutations I can think of, but
cannot get the desired (expected?) results.

The values live in x and the corresponding semi-regular time stamps are in
t:
> library('zoo')
> z = zoo(x, order.by=t, frequency=24)
> zzr = as.zooreg(z, start=0)
> zr = zooreg(x, order.by=t, start=0, frequency=24)
> zrz = as.zoo(zr)
The objects z, zr, and zzr all have frequency 24, as desired, and plot
correctly. Object zrz plots correctly but has frequency 1. Now I try to make
it a ts object:
> zrt = ts(zzr)
... omits the missing values.
> zrt = ts(zzr, frequency=24)
... omits the missing values and changes the timestamps.
> plot(ts(zr))
... omits the missing values.
> zrt = ts(zr, frequency=24)
... omits the missing values and changes the timestamps.
> zrt = as.ts(zr)
... inserts 23 NA values between each legitimate value.
> zrt = as.ts(zr, frequency=24)
... inserts 23 NA values between each legitimate value.
> zrzt = ts(zrz)
... omits the missing values.
> zrzt = ts(zrz, frequency=24)
... omits the missing values and changes the timestamps.

Could someone tell me how to get the desired ts object?

Sincerely,
-- 
 - Adam J. Oliner

	[[alternative HTML version deleted]]

On Tue, Jan 18, 2011 at 6:33 PM, Adam Oliner <oliner at gmail.com>
wrote:
> Hi,
>
> I'm trying to make a ts object that has both NA values and a frequency
other
> than 1 (so I can use stl). I've tried all permutations I can think of,
but
> cannot get the desired (expected?) results.
>
> The values live in x and the corresponding semi-regular time stamps are in
> t:
>
>> library('zoo')
>> z = zoo(x, order.by=t, frequency=24)
>> zzr = as.zooreg(z, start=0)
>> zr = zooreg(x, order.by=t, start=0, frequency=24)
>> zrz = as.zoo(zr)
>
> The objects z, zr, and zzr all have frequency 24, as desired, and plot
> correctly. Object zrz plots correctly but has frequency 1. Now I try to
make
> it a ts object:
>
>> zrt = ts(zzr)
> ... omits the missing values.
>> zrt = ts(zzr, frequency=24)
> ... omits the missing values and changes the timestamps.
>> plot(ts(zr))
> ... omits the missing values.
>> zrt = ts(zr, frequency=24)
> ... omits the missing values and changes the timestamps.
>> zrt = as.ts(zr)
> ... inserts 23 NA values between each legitimate value.
>> zrt = as.ts(zr, frequency=24)
> ... inserts 23 NA values between each legitimate value.
>> zrzt = ts(zrz)
> ... omits the missing values.
>> zrzt = ts(zrz, frequency=24)
> ... omits the missing values and changes the timestamps.
>
Note that there is an as.ts.zoo method.


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