python - Initial node's ids when creating graph from edge list -
i wonder, function read_edgelist store original id's the edge list? or under attribute name? assume reading edge list like: 1 2 2 1 1 3 where numbers 1,2,3 ids (or names) of nodes. igraph (python version) stores these ids? tried retrieving these ids attribute name or id did not work, 2 attributes, seemingly, must explicitly defined. read_edgelist assumes node ids consecutive integers 0 m, m maximum integer in edge list. there "no need store node ids." for example, if edgelist.txt 1 3 , code import igraph ig g = ig.graph.read_edgelist("edgelist.txt") print g.get_adjacency() creates graph 4 nodes (0, 1, 2, 3) , prints [[0, 0, 0, 0] [0, 0, 0, 1] [0, 0, 0, 0] [0, 0, 0, 0]] see answer if not want "intermediate" nodes created. while following unnecessary graph consecutive node ids starting 0, 1 access node ids using vertexseq , vertex : for v in g.vs: print v.index # node id