[R] Merge data frame and keep unmatched

[Gabor Grothendieck]

Try:

merge(completedf, partdf, all.x = TRUE)

or

library(sqldf) # see http://sqldf.googlecode.com
sqldf("select * from completedf left join partdf using(beta, alpha)")


On Wed, Jun 10, 2009 at 9:56 AM, Etienne B. Racine<etiennebr at gmail.com> wrote:
>
> Hi,
>
> With two data sets, one complete and another one partial, I would like to
> merge them and keep the unmatched lines. The problem is that merge() dosen't
> keep the unmatched lines. Is there another function that I could use to
> merge the data frames.
>
> Example:
>
> completedf <- expand.grid(alpha=letters[1:3],beta=1:3)
> partdf <- data.frame(
>        alpha= c('a','a','c'),
>        beta = c(1,3,2),
>        val = c(2,6,4))
>
> mergedf <- merge(x=completedf, y=partdf, by=c('alpha','beta'))
> # it only kept the common rows
> nrow(mergedf)
>
> Thanks,
> Etienne
> --
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