R help - May 2012 - select month data in ts objects

In a time series ts object, like the z1.ts below:

z1 = array(1:235)

z1.ts = ts(z1, frequency =12)

I would like to select only a certain month, for instance the
"February"
data

If I transform the data to a matrix, I have the problem that 235 is not 
a multiple of 12

I do not like to cut or add data, or program a loop to pick out the 
correct data.

I am wondering if exist an easier way to select month data in a ts object.

Thank you a lot for your help.

SGeco


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On Wed, May 2, 2012 at 4:27 PM, S. Georgakarakos <stratisg at aegean.gr>
wrote:
> In a time series ts object, like the z1.ts below:
>
> z1 = array(1:235)
>
> z1.ts = ts(z1, frequency =12)
>
> I would like to select only a certain month, for instance the
"February"
> data
>
> If I transform the data to a matrix, I have the problem that 235 is not
> a multiple of 12
>
> I do not like to cut or add data, or program a loop to pick out the
> correct data.
>
> I am wondering if exist an easier way to select month data in a ts object.
>
Use cycle:

tt <- ts(1:235, frequency =12)
ts(tt[cycle(tt) == 2])


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