On Mon, Apr 4, 2011 at 1:09 PM, Dimitri Liakhovitski
<dimitri.liakhovit...@gmail.com> wrote:
> Hello!
> I have my data frame "mydata" (below) and data frame "reference" -
> that contains all the dates I would like to be present in the final
> data frame.
> I am trying to merge them so that the the result data frame contains
> all 8 dates in both subgroups (i.e., Group1 should have 8 rows and
> Group2 too). But when I merge it it's not coming out this way. Any
> hint would be greatly appreciated!
> Dimitri
>
> mydata<-data.frame(mydate=rep(seq(as.Date("2008-12-29"), length = 8,
> by = "week"),2),
> group=c(rep("Group1",8),rep("Group2",8)),values=rnorm(16,1,1))
> (reference);(mydata)
> set.seed(1234)
> out<-sample(1:16,5,replace=F)
> mydata<-mydata[-out,]; dim(mydata)
> (mydata)
>
> # "reference" contains the dates I want to be present in the final data frame:
> reference<-data.frame(mydate=seq(as.Date("2008-12-29"), length = 8, by
> = "week"))
>
> # Merging:
> new.data<-merge(mydata,reference,by="mydate",all.x=T,all.y=T)
> new.data<-new.data[order(new.data$group,new.data$mydate),]
> (new.data)
> # my new.data contains only 7 rows in Group 1 and 4 rows in Group 2
>
It might make more sense to put each group into its own column since
then the object is a multivariate time series:
> library(zoo)
> z <- merge(read.zoo(mydata, split = 2), zoo(, reference[[1]]), all = c(FALSE,
> TRUE))
> z
Group1 Group2
2008-12-29 2.0266215 NA
2009-01-05 NA NA
2009-01-12 1.0255344 NA
2009-01-19 1.3880938 0.8135788
2009-01-26 1.4380978 1.6068682
2009-02-02 1.1764965 NA
2009-02-09 1.1578531 1.4484447
2009-02-16 0.6673568 1.4760864
although if you really need to you could string them out like this:
library(reshape2)
melt(data.frame(time(z), coredata(z)), id = 1)
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