Union of graphs

graph.union() was renamed to union.igraph() to create a more consistent API.

graph.union(..., byname = "auto")

Arguments

...

Graph objects or lists of graph objects.

byname

A logical scalar, or the character scalar auto. Whether to perform the operation based on symbolic vertex names. If it is auto, that means TRUE if all graphs are named and FALSE otherwise. A warning is generated if auto and some (but not all) graphs are named.