[R] Correcting for missing data combinations

[Charles C. Berry]

On Fri, 11 Dec 2009, GL wrote:

>
> I can think of many brute-force ways to do this outside of R, but was
> wondering if there was a simple/elegant solution within R instead.
>
> I have a table that looks something like the following:
>
> Factor1	Factor2		Value
> A	11/11/2009	5
> A	11/12/2009	4
> B	11/11/2009 	7
> B	11/13/2009	8
>
>> From that I need to generate all permutations of Factor1 and Factor2 and
> force a 0 for any combination that doesn’t exist in the actual data table.
> By way of example, I’d like the output for above to end up as:
>
> Factor1	Factor2		Value
> A	11/11/2009	5
> A	11/12/2009	4
> A	11/13/2009	0
> B	11/11/2009 	7
> B	11/12/2009	0
> B	11/13/2009	8
>
> Truly appreciate any thoughts.

# copy the 'table' to the clipboard, then:

> dat <- read.table("clipboard",header=T)
> res <- as.data.frame(xtabs(Value~., dat ))
> colnames(res) <- sub("Freq","Value",colnames(res))
> res
   Factor1    Factor2 Value
1       A 11/11/2009     5
2       B 11/11/2009     7
3       A 11/12/2009     4
4       B 11/12/2009     0
5       A 11/13/2009     0
6       B 11/13/2009     8
>

HTH,

Chuck


>
> -- 
> View this message in context: http://n4.nabble.com/Correcting-for-missing-data-combinations-tp961301p961301.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> R-help at 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.
>

Charles C. Berry                            (858) 534-2098
                                             Dept of Family/Preventive Medicine
E mailto:cberry at tajo.ucsd.edu	            UC San Diego
http://famprevmed.ucsd.edu/faculty/cberry/  La Jolla, San Diego 92093-0901