search for: outcloseness_social

I am using the code below to output some network measures: central_social <- data.frame(V(s641_social)$name, indegree_social, outdegree_social, incloseness_social, outcloseness_social, betweenness_social, eigen_social) and I get the following error: Error in Re(z) : non-numeric argument to function I know this has to do with V but I cannot figure out what is wrong. s641-social is a graph object and the vertices do have a name attribute. What can I do to fix? Thanks -- Vie...