Character constant giving the file format. Right now
as_edgelist, pajek, graphml, gml, ncol, lgl, dimacs, graphdb and igraph are
supported
numbers
A logical value indicating if the names of the nodes are
values.This argument is settable for the edgelist format.
The default is FALSE.
directed
A logical value indicating if is a directed graph. The
default is FALSE.
header
A logical value indicating whether the file contains
the names of the variables as its first line.This argument is settable
for the edgelist format.The default is FALSE.
Value
An igraph object, which do not contain loop and multiple edges.