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TGF

The Trivial Graph Format (TGF) is a minimal, plain-text adjacency-list format commonly used to exchange small graphs. Gephi includes an importer that supports the common TGF variant where nodes are listed first (one per line), followed by a line containing only #, then edges (one per line). Node lines map an ID to an optional label; edge lines list source and target node IDs and an optional edge label.

Format summary​

  • Node section: one node per line with ID [label].
  • Separator: a line containing only # separates nodes from edges.
  • Edge section: one edge per line with sourceID targetID [label].

Whitespace is used to separate fields. Labels may contain spaces when they follow the first space on the line.

Example​

Minimal example with two nodes and one labeled edge:

1 First node
2 Second node
#
1 2 connecting edge

Gephi importer behaviour​

Gephi's importer supports the common TGF variant described above. Key behaviours:

  • Lines before the # are node definitions: the first token is the node ID; any text after the first space is used as the label. If no label is provided the ID will be used as the label.
  • Lines after the # are edge definitions: the first token is the source ID, the second token is the target ID; any remaining text after the second token is used as the edge label.

Limitations and notes​

  • The importer assumes IDs are whitespace-free tokens.
  • Labels are taken as the remainder of the line after the first (for nodes) or second (for edges) space; leading spaces in labels are preserved by substring logic.