[R] How to aggregate combinations

[Rui Barradas]

Hello,

The problem can be solved using graph theory tools.

library(igraph)

edg <- read.table(text="
ID ID2
1    2
1    3
2    3
6    5
7    8
8    9
", header=TRUE)

(G <- graph(t(edg) - 1, directed=TRUE))  # igraph vertices are zero-based
V(G)$name <- 1:9

#V(G)$label <- V(G)$name
#plot(G, layout=layout.circle)

comp <- decompose.graph(G)
lapply(comp, function(x) colnames(get.adjacency(x)))

Hope this helps,

Rui Barradas

Em 30-05-2012 22:01, Oritteropus escreveu:
> Hi all,
> Given a table like the one below, I want to get a number of vectors equal to
> the groups of connected ID (ID are considered connected if they are in the
> same row). Each vector should contains all the connected ID .
>
> e.g. In this case: vect1  (1,2,3)         vect2  (5,6)     vect3 (7,8,9)
>
> ID ID2
> 1    2
> 1    3
> 2    3
> 6    5
> 7    8
> 8    9
>
> Does someone know how to do it automatically for tables with thousands of
> rows?
> Thanks a lot
>
> --
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