[R] A list of data.frames merged together

[Gabor Grothendieck]

This will do it:

> merge(A, B, by = 1, all = TRUE)
      Date Value.x Value.y
1 03/15/10       1       5
2 04/15/10       2       5
3 05/15/10       3      NA
4 06/15/10      NA       5

but you probably really want to be using time series for this so that
you can easily perform other operations too. See ?merge.zoo and the
three zoo vignettes for more.

> library(zoo)
> library(chron)
> za <- zoo(A$Value, chron(as.character(A$Date)))
> zb <- zoo(B$Value, chron(as.character(B$Date)))
> merge(za, zb)
         za zb
03/15/10  1  5
04/15/10  2  5
05/15/10  3 NA
06/15/10 NA  5

> zm <- merge(za, zb)

> # convert to data frame
> cbind(Date = time(zm), as.data.frame(zm))
             Date za zb
03/15/10 03/15/10  1  5
04/15/10 04/15/10  2  5
05/15/10 05/15/10  3 NA
06/15/10 06/15/10 NA  5

> # handle more than two at a time
> merge(za, za2 = za, zb)
         za za2 zb
03/15/10  1   1  5
04/15/10  2   2  5
05/15/10  3   3 NA
06/15/10 NA  NA  5

> # same but series are in a list
> do.call(merge, list(za = za, za2 = za, zb = zb))
         za za2 zb
03/15/10  1   1  5
04/15/10  2   2  5
05/15/10  3   3 NA
06/15/10 NA  NA  5

On Tue, Mar 9, 2010 at 11:21 AM, Daniel Brewer <daniel.brewer at icr.ac.uk> wrote:
> Hello,
>
> I have for a long list of data.frames that I would like to get merged.
> Each data.frame have two columns with the same names (Date and Value).
> What I would like is for the objects in the list to be merged on Only
> date with the column header being the name in the list.
>
> For example
>
> A <- data.frame(Date=c("03/15/10","04/15/10","05/15/10"),
> Value=c(1,2,3))
> B <- data.frame(Date=c("03/15/10","04/15/10","06/15/10"),
> Value=c(5,5,5))
> ...
>
> yoda <- list(A=A,B=B,...)
>
> Result:
>
> Date            A       B       C
> 03/15/10        1       5       ...
> 04/15/10        2       5
> 05/15/10        3       NA
> 06/15/10        NA      5
>
> Any ideas? I have been fiddling around with plyr and reshape without success
>
> Thanks
>
> Dan
>
> --
> **************************************************************
>
> Daniel Brewer, Ph.D.
>
> Institute of Cancer Research
> Molecular Carcinogenesis
> MUCRC
> 15 Cotswold Road
> Sutton, Surrey SM2 5NG
> United Kingdom
>
> Tel: +44 (0) 20 8722 4109
>
> **************************************************************
>
> The Institute of Cancer Research: Royal Cancer Hospital, a charitable Company Limited by Guarantee, Registered in England under Company No. 534147 with its Registered Office at 123 Old Brompton Road, London SW7 3RP.
>
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