Re: [igraph] as.undirected() strips vertex attributes?

[Tamas Nepusz]

> But i guess we can implement it for the obvious cases, and give
> and warning about attributes getting dropped when it is not possible
> to do it with this naive implementation.
IMHO: graph attributes should be kept no matter which direction
(undirected to directed or vice versa) is being used. The same with
vertex attributes.
Edge attributes should be kept when there exists a one-to-one or
one-to-many mapping of the old edges to the new ones (attributes
should be copied in the case of one-to-many mapping). The only
ambiguous case is the conversion to undirected with
IGRAPH_TO_UNDIRECTED_COLLAPSE. I think a simple warning is enough in
this case.

-- 
Tamas