On Fri, Dec 10, 2010 at 07:20:55AM -0800, profaar wrote:
>
> HI friends,
> I have very lengthy graph data in edge list format. I want to convert it
> into node list format.
>
> example:
> EDGE LIST FORMAT
> 1 2
> 1 3
> 1 4
> 1 5
> 2 3
> 2 4
> 3 2
> 4 1
> 4 3
> 4 5
> 5 2
> 5 4
>
> ITS NODE LIST FORMAT SHOULD BE LIKE:
> 1 2 3 4 5
> 2 3 4
> 3 2
> 4 1 3
> 5 2 4
>
> Kindly suggest me which package in R provides the support to do my task.
How long the list of egdes is? For not too large lists, consider also
library(graph)
G <- new("graphNEL", edgemode="directed")
G <- addNode(as.character(1:5), G)
edges <- read.table(file=stdin(), colClasses="character")
1 2
1 3
1 4
1 5
2 3
2 4
3 2
4 1
4 3
4 5
5 2
5 4
G <- addEdge(from=edges[, 1], to=edges[, 2], G)
edgeL(G)
$`1`
$`1`$edges
[1] 2 3 4 5
$`2`
$`2`$edges
[1] 3 4
$`3`
$`3`$edges
[1] 2
$`4`
$`4`$edges
[1] 1 3 5
$`5`
$`5`$edges
[1] 2 4
Very large lists can be handled by unix/linux sort command (if not sorted
already) and by extracting the end-nodes of the edges starting in each node.
In a sorted file, they form blocks of consecutive lines, so a simple text
processing with perl is sufficient.
Petr Savicky.
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