2-column source->target dataframe to link and node lists?

[areeves87]

Is there a native munging function for getting a 2-column (source->target) data.frame into a link list and node list format?

The 2-column dataframe has the following format

Source	Target
A	C
A	D
B	E
B	F

The link list would be:

from	to
0	2
0	3
1	4
1	5

and the node list would be

id	node
0	A
1	B
2	C
3	D
4	E
5	F

I can get the data into this format but I want to know if there are standard methods for doing so?

[cjyetman]

At the moment, no, there is no exported function to do specifically that task. The simpleNetwork function does that internally before passing on to forceNetwork with...

# create nodes data
node_names <- factor(sort(unique(c(as.character(sources), as.character(targets)))))
nodes <- data.frame(name = node_names, group = 1, size = 8)

# create links data
links <- data.frame(source = match(sources, node_names) - 1,
                    target = match(targets, node_names) - 1,
                    value = 1)

I’ve been working on a major overhaul of networkD3 that has an exported data conversion function that would handle that situation, among many other data types, automatically, but I haven’t committed any of it yet. It’s likely that igraph and/or tidygraph have something like that too.