On Mar 4, 2012, at 4:51 AM, Ajay Askoolum wrote:

I know how to do this when creating the time series variable in one expression, e.g.

valuesTS1<-ts(values,start=2000); # Frequency naturally defaults to 1


How can I specify the frequency of a time series?


I do not see a `frequency<-` usage illustrated on the ?frequency page, but the method of specifying "frequency" on the ?ts page does seem fairly obvious.

It wasn't obvious to me whether ts() could gracefully coerce an existing ts-object if only offered the object and a new frequency parameter. Testing, however, shows that such coercion does not result in keeping the original start parameter. Efforts to alter only the third tsp() attribute likewise failed for me.

Using the example on the ?ts page in the absece of the requested reproducible code. it looks like the effective procedure is to recover the start parameter and offer an altered frequency parameter:

> test.ts <- ts(1:10, frequency = 4, start = c(1959, 2)) # 2nd Quarter of 1959

> test.ts <- ts(test.ts, frequency = 8)
> test.ts
Time Series:
Start = c(1, 1)
End = c(2, 2)
Frequency = 8
 [1]  1  2  3  4  5  6  7  8  9 10

# Note that the start parameter was removed

# This seems to "work".

> test.ts <- ts(1:10, frequency = 4, start = c(1959, 2)) # 2nd Quarter of 1959

> ts(test.ts, start=start(test.ts), frequency=12)
     Feb Mar Apr May Jun Jul Aug Sep Oct Nov
1959   1   2   3   4   5   6   7   8   9  10
--


values=c(12,34,65,12);
values<-ts(values);
frequency(values);
[1] 1
start(values)
[1] 1 1
frequency(values)<-12;
Error in frequency(values) <- 12 : could not find function "frequency<-"

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