A data frame containing a symbolic edge list in the first two columns.
Additional columns are considered as edge attributes.
Since version 0.7 this argument is coerced to a data frame with as.data.frame.
directed
Logical scalar, whether or not to create a directed graph.
vertices
A data frame with vertex metadata, or NULL.
Since version 0.7 of igraph this argument is coerced to a data frame with as.data.frame, if not NULL.