The intersection of two or more graphs are created. The graphs may have identical or overlapping vertex sets.
# S3 method for class 'igraph'
intersection(..., byname = "auto", keep.all.vertices = TRUE)Graph objects or lists of graph objects.
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.
Logical scalar, whether to keep vertices that only appear in a subset of the input graphs.
A new graph object.
intersection() creates the intersection of two or more graphs:
only edges present in all graphs will be included. The corresponding
operator is %s%.
If the byname argument is TRUE (or auto and all graphs
are named), then the operation is performed on symbolic vertex names instead
of the internal numeric vertex ids.
intersection() keeps the attributes of all graphs. All graph,
vertex and edge attributes are copied to the result. If an attribute is
present in multiple graphs and would result a name clash, then this
attribute is renamed by adding suffixes: _1, _2, etc.
The name vertex attribute is treated specially if the operation is
performed based on symbolic vertex names. In this case name must be
present in all graphs, and it is not renamed in the result graph.
An error is generated if some input graphs are directed and others are undirected.
Other functions for manipulating graph structure:
+.igraph(),
add_edges(),
add_vertices(),
complementer(),
compose(),
connect(),
contract(),
delete_edges(),
delete_vertices(),
difference(),
difference.igraph(),
disjoint_union(),
edge(),
igraph-minus,
intersection(),
path(),
permute(),
rep.igraph(),
reverse_edges(),
simplify(),
union(),
union.igraph(),
vertex()
## Common part of two social networks
net1 <- graph_from_literal(
D - A:B:F:G, A - C - F - A, B - E - G - B, A - B, F - G,
H - F:G, H - I - J
)
net2 <- graph_from_literal(D - A:F:Y, B - A - X - F - H - Z, F - Y)
print_all(net1 %s% net2)
#> IGRAPH e3a7ca1 UN-- 13 4 --
#> + attr: name (v/c)
#> + vertex attributes:
#> | name
#> | [1] D
#> | [2] A
#> | [3] B
#> | [4] F
#> | [5] G
#> | [6] C
#> | [7] E
#> | [8] H
#> | [9] I
#> | [10] J
#> | [11] Y
#> | [12] X
#> | [13] Z
#> + edges from e3a7ca1 (vertex names):
#> [1] F--H A--B D--F D--A