Think Like (a) Git

Attaching Labels to Edges

Just as we can label the nodes in a graph, we can also attach information to the edges. This might include:

• Names—for example, "12th Avenue".
• Numbers (also called "weights")—like distances or speeds.
• Types—to denote relationships, like "friend" or "coworker" or "parent of".
• Direction—in the previous example, relationships like "friend" and "coworker" are bidirectional, but "parent of" only goes one way (unless, possibly, you're a character in a Robert A. Heinlein novel).

In fact, that last point about directionality is so important that it deserves its own page.