[R] A list of data.frames merged together

Phil Spector spector at stat.berkeley.edu
Tue Mar 9 18:09:21 CET 2010


Daniel -
    Reduce may be handy here:

ans = Reduce(function(a,b)merge(a,b,by=1),yoda)
names(ans)[2:ncol(ans)] = names(yoda)

 					- Phil Spector
 					 Statistical Computing Facility
 					 Department of Statistics
 					 UC Berkeley
 					 spector at stat.berkeley.edu




On Tue, 9 Mar 2010, Daniel Brewer 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
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>
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>
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>
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