[igraph] how to change x type attribute to numeric type attribute?

[Fatemeh a]

Hi,

I was wondering how could I resolve this issue :

after using 

  graph_simplify=simplify(graph,remove.multiple = TRUE,edge.attr.comb=list(Weight="mean"))

and the type of the edge attribute weight

change from n(numeric) to x(other) and when i execute sum(E(graph)$weight) , I got zero , how should I change the x type attribute to numeric one ?

thank you in advance,

--

regards

F..A