Graphlet GML (Graph Modelling Language) is a text-based file format for storing a single directed or undirected graph.

The GraphTheory[ImportGraph] and GraphTheory[ExportGraph] commands can read from and write to this format.

The general-purpose commands Import and Export also support this format.

$\mathrm{Petersen}≔\mathrm{Import}\left(''example/petersen.gml''\,\mathrm{base}=\mathrm{datadir}\right)$

$\mathrm{Petersen}≔\mathrm{Graph\; 1:\; an\; undirected\; unweighted\; graph\; with\; 10\; vertices\; and\; 15\; edge(s)}$

$\mathrm{GraphTheory}:-\mathrm{DrawGraph}\left(\mathrm{Petersen}\right)$

$\mathrm{Draco}≔\mathrm{Import}\left(''example/draco.gml''\,\mathrm{base}=\mathrm{datadir}\right)$

$\mathrm{Draco}≔\mathrm{Graph\; 2:\; an\; undirected\; unweighted\; graph\; with\; 14\; vertices\; and\; 14\; edge(s)}$

$\mathrm{GraphTheory}:-\mathrm{DrawGraph}\left(\mathrm{Draco}\right)$

$\mathrm{HerschelG}≔\mathrm{GraphTheory}:-\mathrm{SpecialGraphs}:-\mathrm{HerschelGraph}\left(\right)$

$\mathrm{HerschelG}≔\mathrm{Graph\; 3:\; an\; undirected\; unweighted\; graph\; with\; 11\; vertices\; and\; 18\; edge(s)}$

$\mathrm{Export}\left(''herschel.gml''\,\mathrm{HerschelG}\,\mathrm{base}=\mathrm{homedir}\right)$

$1225$