Dear Michael,
Thanks for your prompt response.
na.approx in zoo does fine if we have some time metric. But in my case, we
don't know the time points which the data values correspond to.
The given values in x and y are irregularly observed values at unequal
distances in time.
My objective is just to get 20 equally spaced values interpolating the
given 5/9 observations (no worries about the corresponding time points).

Tsegaye

On Sat, Dec 24, 2011 at 11:46 PM, R. Michael Weylandt <
michael.weylandt@gmail.com> wrote:

> zoo:::na.approx will do nicely. Though you are going to have to supply
> some sort of time metric or it won't know where interpolations should
> happen.
>
> Something like this is my usual route:
>
> x <- zoo(1:5, Sys.Date() + 2*(1:5))
>
> x.new <- zoo(NA, seq(min(time(x)), to =  max(time(x)), by = "day"))
>
> x.new[time(x)] <- x
>
> na.approx(x.new)
>
> Michael
>
> On Sat, Dec 24, 2011 at 5:39 PM, Alemtsehai Abate <abatealem@gmail.com>
> wrote:
> > Dear R users,
> >
> > I have two irregular time series say x and y. Each series is supposed to
> > cover 20 years. The data looks, for instance:
> > x<-c(200,178, 330, 127, 420) ## only 5 observations out of the expected
> 20
> > annual values
> > y<-c(0.35,-0.18,-0.54,0.78,1.7,-1.1,0.2,1.9,0.49)### only 9 observations
> of
> > the expected 20
> >
> > I need to intepolate each of the series into equally spaced 20 points. Is
> > there a function and library in R to do this please?
> >
> > Many thanks
> >
> > Tsegaye
> >
> >        [[alternative HTML version deleted]]
> >
> > ______________________________________________
> > R-help@r-project.org mailing list
> > https://stat.ethz.ch/mailman/listinfo/r-help
> > PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> > and provide commented, minimal, self-contained, reproducible code.
>



-- 
Alemtsehai Abate Turasie,
Climate Theme PhD student at Exeter Climate System,www.secam.ex.ac.uk/xcs
School of Engineering, Computing and Mathematics,
University of Exeter,
North Park Road, EX 4 4QF, Exeter, UK
Harrison building room 319,
Phone: 07405992715,
e-mail: aatt201@exeter.ac.uk,

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