An existing attribute with the same name is overwritten.
See also
Vertex, edge and graph attributes
delete_edge_attr()
,
delete_graph_attr()
,
delete_vertex_attr()
,
edge_attr()
,
edge_attr<-()
,
edge_attr_names()
,
graph_attr()
,
graph_attr<-()
,
graph_attr_names()
,
igraph-attribute-combination
,
igraph-dollar
,
igraph-vs-attributes
,
set_edge_attr()
,
set_vertex_attr()
,
vertex_attr()
,
vertex_attr<-()
,
vertex_attr_names()