[igraph] graph.data.frame

[Simone Gabbriellini]

Hello List,

when I try to build a graph from a data.frame, I have this warning:

> g<-graph.data.frame(data, directed=TRUE, vertices=data2)
Warning messages:
1: In if (class(newval) == "factor") { :
  la condizione la lunghezza > 1 e solo il promo elemento verrà utilizzato
2: In if (class(newval) == "factor") { :
  la condizione la lunghezza > 1 e solo il promo elemento verrà utilizzato

I would like to understand better what the warning is about (since the italian 
translation is meaningless). What I know for sure is that data2 contains more 
nodes than data, because there are a lot of isolates nodes in this network.

is this a possible explanation of the warning?

thanks,
Simone Gabbriellini