[R] Understanding TS objects

[JEFFERY REICHMAN]

R Help Community

I'm trying to understand time series (TS) objects.  Thought I understood but recently have run into a series of error messages that I'm not sure how to handle.  I have 15 years of quarterly data and I typically create a TS object via something like...

data.ts <- ts(mydata, start = 2002, frequency = 4)

this create a matric as opposed to a vector object as I receive a univariate error when I try to decompose the data using the STL function

data.stl <- stl(data.ts, "periodic")
Error in stl(data.ts, "periodic") : only univariate series are allowed

ok so

is.vector(data.ts)
[1] FALSE

so to convert to a vector I'll use
data.ts <- as.vector(data.ts)

but then I lose the frequency as the periods as the data becomes frequency = 1
data.ts <- stl <- stl(data.ts, "periodic")
Error in stl(data.ts, "periodic") :
   series is not periodic or has less than two periods.

So am I missing a  parameter or is there a more general/proper way to create a time series object? First time I've run into this problem .  I can always decompose  via an alternative methods so there are work arounds.  But just trying to understand what I'm not doing programmatically at this point.

Jeff Reichman