Plotting a igraph network with DiagrammeR

Question

I would like to create this simple igraph plot:

library(igraph)
mydata <- data.table(from=c("John", "John", "Jim"),to=c("John", "Jim", "Jack"))
mygraph <- graph_from_data_frame(d=mydata, directed=T)
plot(mygraph, vertex.label.dist=2)

With diagrammeR

library(DiagrammeR)
mygraph2 <- from_igraph(mygraph)
grViz(mygraph2)

Produces this error

Error in file.exists(diagram) : invalid 'file' argument

I've also tried with

grViz(readLines(mygraph2))

and other combinations or the command plot() but I can't find the proper way.

How can I do it?

I've openen a new question to get the same result directly with DiagrammeR, without igraph:

How to create a network graph with DiagrammeR?

user20650 user20650 · Accepted Answer · 2017-06-25T17:37:57

There seems to be a couple of things going on.

library(igraph)
library(DiagrammeR)

mydata <- data.table(from=c("John", "John", "Jim"),to=c("John", "Jim", "Jack"))
mygraph <- graph_from_data_frame(d=mydata, directed=TRUE)

The following code throws an warning

mygraph2 <- from_igraph(mygraph)

Warning messages: 1: In data.frame(from = as.integer(igraph::ends(igraph, igraph::E(igraph))[, : NAs introduced by coercion

And if you look at mygraph2 there is no node or edge info, and it doesnt render : render_graph(mygraph2). But the warning is informative as it points to the lines of code ( as.integer(ends(mygraph, E(mygraph), names=TRUE)) : maybe we want names=FALSE) , so try removing names , but set labels

V(mygraph)$label = V(mygraph)$name
V(mygraph)$name = factor(V(mygraph)$name, levels=as.character(V(mygraph)$name))

No warning and renders

mygraph2 <- from_igraph(mygraph)
render_graph(mygraph2)

If you want to see the dot code you can use generate_dot , and then pass this to grViz, however, this is what render_graph is doing.

grViz(generate_dot(mygraph2))

Plotting a igraph network with DiagrammeR

2 Answers