Not entirely sure why you would want a data.frame that has multiple entries
in one of the columns (Connect.down) but leaving that aside is the following
of any use?
nn=list()
nn[[1]] = list(Node = "1", Connect.up = c(NULL), Connect.down = c(2,3))
nn[[2]] = list(Node = "2", Connect.up = c(1), Connect.down = c(4,5))
nn[[3]] = list(Node = "3", Connect.up = c(NULL), Connect.down = c(2,3))
nn[[4]] = list(Node = "4", Connect.up = c(1), Connect.down = c(4,5))
Output = do.call(as.data.frame(rbind),nn)
# Output
value.Node value.Connect.up value.Connect.down
1 1 NULL 2, 3
2 2 1 4, 5
3 3 NULL 2, 3
4 4 1 4, 5
HTH
Pete
dkStevens wrote
>
> Group
>
> It's unlikely I'm trying this the best way, but I'm trying to create a
> data structure from elements like
>
> nNode = 2
> nn = vector("list",nNode)
>
> nn[[1]] = list(Node = "1", Connect.up = c(NULL), Connect.down = c(2,3))
> nn[[2]] = list(Node = "2", Connect.up = c(1), Connect.down = c(4,5))
> .... #( and eventually many more nodes)
>
> NodeList = as.data.frame(nn[[1]])
> for(i in 2:nNode) {
> NodeList = rbind(NodeList,as.data.frame(nn[[i]]))
> }
>
> and is trying to create a data frame with many rows and three columns:
> Node, Connect.up,Connect.down
> in which the Connect.up and Connect.down columns may be single numbers
> or vectors of numbers. The above approach gives an error:
>
> Error in data.frame(Node = "1", Connect.up = NULL, Connect.down = c(2, :
> arguments imply differing number of rows: 1, 0, 2
>
> My earlier try by brute force worked fine:
>
> NodeList = as.data.frame(rbind(nn[[1]],nn[[2]]))
>
> > NodeList
> Node Connect.up Connect.down
> 1 1 NULL 2, 3
> 2 2 1 4, 5
>
> and gives me what I want (many more rows eventually). But I want to do
> this generically from the problem context in a procedure so I won't know
> up front how many nodes I'll have.
>
> Clearly I'm not understanding how referencing works for lists like I've
> created. Can anyone shed light on this?
>
> --
> David K Stevens, P.E., Ph.D., Professor
> Civil and Environmental Engineering
> Utah Water Research Laboratory
> 8200 Old Main Hill
> Logan, UT 84322-8200
> 435 797 3229 - voice
> 435 797 1363 - fax
> david.stevens@
>
>
>
>
> [[alternative HTML version deleted]]
>
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