Re: [igraph] igraph output header

[Tamas Nepusz]

> Why is some times python-igraph prints different summary information?
> I tried two undirected weighted graphs, and found the header to be
> different:
> 
> First graph:
> 
> IGRAPH U-W- 4 5 --
> [...]
> 
> Second graph:
> IGRAPH UNW- 3 3 --
> [...]
> 
> What is the difference between U-W and UNW in the header?
This is a shorthand notation for the type of the graph. The first character is
always U or D; U is for undirected graphs, D is for directed ones. The second
character is N if the graph is named (in other words, it has a "name" vertex
attribute); otherwise it is a dash. The third character is W if the graph is
weighted (it has a "weight" edge attribute) and a dash otherwise. The fourth
character is T if the graph is typed (it has a "type" vertex attribute) and
a dash otherwise. These will be documented somewhere but I'm not sure how final
the format is -- it might change in the future.

-- 
T.