R help - Jun 2010 - recursively Merging a list a zoo objects

The zoo package as a merge function which merges a set of zoo objects
result<-merge(zoo1,zoo2,...)

Assume your zoo objects are already collected in a list

# make a phony list to illustrate the situation. ( hat tip to david W for
constructing a list in a loop)

ddat <- as.list(rep("", 20))
 ytd<-seq(3,14)
 for(i in 1:20) {
+ ddat[[i]] <- zoo(data,ytd )
+ }


ddat
[[1]]
 1  2  3  4  5  6  7  8  9 10 11 12
 3  4  5  6  7  8  9 10 11 12 13 14

[[2]]
 1  2  3  4  5  6  7  8  9 10 11 12
 3  4  5  6  7  8  9 10 11 12 13 14

[[3]]
 1  2  3  4  5  6  7  8  9 10 11 12
 3  4  5  6  7  8  9 10 11 12 13 14

........

So given a list of zoo objects, if you want to create a merged  zoo object
is there a way to do that.

For example, merging the first two gives you this

result<-merge(ddat[[1]],ddat[[2]])
> result
   ddat[[1]] ddat[[2]]
3          3         3
4          4         4
5          5         5
6          6         6
7          7         7
8          8         8
9          9         9
10        10        10
11        11        11
12        12        12
13        13        13
14        14        14

And..

result<-merge(result,ddat[[3]])
> result
   ddat[[1]] ddat[[2]] ddat[[3]]
3          3         3         3
4          4         4         4
5          5         5         5
6          6         6         6
7          7         7         7
8          8         8         8
9          9         9         9
10        10        10        10
11        11        11        11
12        12        12        12
13        13        13        13
14        14        14        14

I'm thinking that either do.call or lapply should do the trick.. or a
combination of the two. It would appear to be a straightforward
recursion applying merge to the result of merge..the looping solution is
straightforward

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On Mon, Jun 14, 2010 at 6:13 PM, steven mosher <moshersteven at gmail.com>
wrote:
> The zoo package as a merge function which merges a set of zoo objects
> result<-merge(zoo1,zoo2,...)
>
> Assume your zoo objects are already collected in a list
>
> # make a phony list to illustrate the situation. ( hat tip to david W for
> constructing a list in a loop)
>
> ddat <- as.list(rep("", 20))
> ?ytd<-seq(3,14)
> ?for(i in 1:20) {
> + ddat[[i]] <- zoo(data,ytd )
> + }
>
>
merge.zoo can handle multiple zoo objects (not just two) so:

   do.call("merge", ddat)

This also works but is a bit tedious:

merge(ddat[[1]], ddat[[2]], ddat[[3]], ddat[[4]], ddat[[5]],
   ddat[[6]], ddat[[7]], ddat[[8]], ddat[[9]], ddat[[10]],
   ddat[[11]], ddat[[12]], ddat[[13]], ddat[[14]], ddat[[15]],
   ddat[[16]], ddat[[17]], ddat[[18]], ddat[[19]], ddat[[20]])

Also note that there is an example of using do.call with merge.zoo in
the examples section of ?merge.zoo