[igraph] Re: Analyzing Graphs with Non-standard Node Labeling

[Lorenzo Isella]

Gábor Csárdi wrote:
> Lorenzo,
>
> On Wed, Jul 8, 2009 at 12:39 PM, Lorenzo Isella<address@hidden> wrote:
>   
> > Hi Gabor,
> > And thanks for your help. This works brilliantly, apart from one case:
> > suppose that  (as it actually happens) my edge list shrinks to only a couple
> > of connected nodes
> > e.g.:
> >
> > 1101 1187
> >
> > Then using graph.data.frame raises an error  (but it is still a  legitimate
> > graph)
> >
> > l<-graph.data.frame(mydata,dir=FALSE)
> > Error in if (ncol(d) < 2) { : argument is of length zero
> >     
>
> What is 'mydata' here? Because graph.data.frame works fine, even if
> the data frame has a single line only:
>
>   
> > library(igraph)
> > df <- data.frame(from=1101, to=1187)
> > l <- graph.data.frame(df, dir=FALSE)
> > l
> >     
> Vertices: 2
> Edges: 1
> Directed: FALSE
> Edges:
>     e
> e [0] '1101' -- '1187'
>
> G.
>
>   
> > There are many ways to tackle this problem, but I would like not to lose the
> > info about the vertex names (i.e. I would like to extend the procedure you
> > suggested even to trivial graphs). The reason I am posting this is that I
> > need to post-process a list of time-evolving networks (automatically) and I
> > do not know beforehand the properties of the network I need to analyze.
> > Many thanks
> >     
>
> [...]
>
>   
Apologies,
I had inadvertently changed the data frame into a something else.
Cheers

Lorenzo