[R] zero-fill absent data

[Gabor Grothendieck]

The zoo package's merge.zoo routines has a fill=0 argument so:  create
an expanded index, ix, and then in the next line create zoo objects
from the data and the expanded index and merge them together.  Finally
in the last line convert back to a data frame.

library(zoo)
ix <- with(frame, seq(min(V1), max(V1)))
z <- with(frame, merge(zoo(V2, V1), zoo(, ix), fill = 0))
data.frame(V1 = time(z), V2 = coredata(z))


On Tue, Jan 5, 2010 at 5:39 PM, Dan Kortschak
<dan.kortschak at adelaide.edu.au> wrote:
> Hello,
>
> I have a set of data frames, generated by an SQL query that I am working
> with. Because of the way the query was written, zero values for the
> dependent variable (V2 in the example) are not recorded. Up until now
> this has not been a problem.
>
> I would like to be able to fill all absent data with 0.
>
> Current state of data (e.g.):
>> frame<-as.data.frame(cbind(c(1:2,5:7),c(0.5,0.2,1,1.6,2)))
>> frame
>  V1  V2
> 1  1 0.5
> 2  2 0.2
> 3  5 1.0
> 4  6 1.6
> 5  7 2.0
>
> So that frame returns:
>
>  V1  V2
> 1  1 0.5
> 2  2 0.2
> 3  3 0.0
> 4  4 0.0
> 5  5 1.0
> 6  6 1.6
> 7  7 2.0
>
>
> Since absent data may be beyond the last recorded point I'd like to be
> able to use a terminating 0
>
>> frame<-as.data.frame(cbind(c(1:2,5:7,10),c(0.5,0.2,1,1.6,2,0)))
>> frame
>  V1  V2
> 1  1 0.5
> 2  2 0.2
> 3  5 1.0
> 4  6 1.6
> 5  7 2.0
> 6 10 0.0
>
> So that values 7<V1<10 are zero filled.
>
> Can anyone suggest a method to do this?
>
> thank you for your time.
> Dan
>
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