These functions find the vertices not farther than a given limit from
another fixed vertex, these are called the neighborhood of the vertex.
Note that ego() and neighborhood(),
ego_size() and neighborhood_size(),
make_ego_graph() and make_neighborhood()_graph(),
are synonyms (aliases).
connect(graph, order, mode = c("all", "out", "in", "total"))
ego_size(
graph,
order = 1,
nodes = V(graph),
mode = c("all", "out", "in"),
mindist = 0
)
neighborhood_size(
graph,
order = 1,
nodes = V(graph),
mode = c("all", "out", "in"),
mindist = 0
)
ego(
graph,
order = 1,
nodes = V(graph),
mode = c("all", "out", "in"),
mindist = 0
)
neighborhood(
graph,
order = 1,
nodes = V(graph),
mode = c("all", "out", "in"),
mindist = 0
)
make_ego_graph(
graph,
order = 1,
nodes = V(graph),
mode = c("all", "out", "in"),
mindist = 0
)
make_neighborhood_graph(
graph,
order = 1,
nodes = V(graph),
mode = c("all", "out", "in"),
mindist = 0
)The input graph.
Integer giving the order of the neighborhood. Negative values indicate an infinite order.
Character constant, it specifies how to use the direction of
the edges if a directed graph is analyzed. For ‘out’ only the
outgoing edges are followed, so all vertices reachable from the source
vertex in at most order steps are counted. For ‘"in"’ all
vertices from which the source vertex is reachable in at most order
steps are counted. ‘"all"’ ignores the direction of the edges. This
argument is ignored for undirected graphs.
The vertices for which the calculation is performed.
The minimum distance to include the vertex in the result.
ego_size()/neighborhood_size() returns with an integer vector.
ego()/neighborhood() (synonyms) returns A list of igraph.vs or a list of numeric
vectors depending on the value of igraph_opt("return.vs.es"),
see details for performance characteristics.
make_ego_graph()/make_neighborhood_graph() returns with a list of graphs.
connect() returns with a new graph object.
The neighborhood of a given order r of a vertex v includes all
vertices which are closer to v than the order. I.e. order 0 is always
v itself, order 1 is v plus its immediate neighbors, order 2
is order 1 plus the immediate neighbors of the vertices in order 1, etc.
ego_size()/neighborhood_size() (synonyms) returns the size of the neighborhoods of the given order,
for each given vertex.
ego()/neighborhood() (synonyms) returns the vertices belonging to the neighborhoods of the given
order, for each given vertex.
make_ego_graph()/make_neighborhood()_graph() (synonyms) is creates (sub)graphs from all neighborhoods of
the given vertices with the given order parameter. This function preserves
the vertex, edge and graph attributes.
connect() creates a new graph by connecting each vertex to
all other vertices in its neighborhood.
Other functions for manipulating graph structure:
+.igraph(),
add_edges(),
add_vertices(),
complementer(),
compose(),
contract(),
delete_edges(),
delete_vertices(),
difference(),
difference.igraph(),
disjoint_union(),
edge(),
igraph-minus,
intersection(),
intersection.igraph(),
path(),
permute(),
rep.igraph(),
reverse_edges(),
simplify(),
union(),
union.igraph(),
vertex()
Other structural.properties:
bfs(),
component_distribution(),
constraint(),
coreness(),
degree(),
dfs(),
distance_table(),
edge_density(),
feedback_arc_set(),
feedback_vertex_set(),
girth(),
is_acyclic(),
is_dag(),
is_matching(),
k_shortest_paths(),
knn(),
reciprocity(),
subcomponent(),
subgraph(),
topo_sort(),
transitivity(),
unfold_tree(),
which_multiple(),
which_mutual()
g <- make_ring(10)
ego_size(g, order = 0, 1:3)
#> [1] 1 1 1
ego_size(g, order = 1, 1:3)
#> [1] 3 3 3
ego_size(g, order = 2, 1:3)
#> [1] 5 5 5
# neighborhood_size() is an alias of ego_size()
neighborhood_size(g, order = 0, 1:3)
#> [1] 1 1 1
neighborhood_size(g, order = 1, 1:3)
#> [1] 3 3 3
neighborhood_size(g, order = 2, 1:3)
#> [1] 5 5 5
ego(g, order = 0, 1:3)
#> [[1]]
#> + 1/10 vertex, from d31eb30:
#> [1] 1
#>
#> [[2]]
#> + 1/10 vertex, from d31eb30:
#> [1] 2
#>
#> [[3]]
#> + 1/10 vertex, from d31eb30:
#> [1] 3
#>
ego(g, order = 1, 1:3)
#> [[1]]
#> + 3/10 vertices, from d31eb30:
#> [1] 1 2 10
#>
#> [[2]]
#> + 3/10 vertices, from d31eb30:
#> [1] 2 1 3
#>
#> [[3]]
#> + 3/10 vertices, from d31eb30:
#> [1] 3 2 4
#>
ego(g, order = 2, 1:3)
#> [[1]]
#> + 5/10 vertices, from d31eb30:
#> [1] 1 2 10 3 9
#>
#> [[2]]
#> + 5/10 vertices, from d31eb30:
#> [1] 2 1 3 10 4
#>
#> [[3]]
#> + 5/10 vertices, from d31eb30:
#> [1] 3 2 4 1 5
#>
# neighborhood() is an alias of ego()
neighborhood(g, order = 0, 1:3)
#> [[1]]
#> + 1/10 vertex, from d31eb30:
#> [1] 1
#>
#> [[2]]
#> + 1/10 vertex, from d31eb30:
#> [1] 2
#>
#> [[3]]
#> + 1/10 vertex, from d31eb30:
#> [1] 3
#>
neighborhood(g, order = 1, 1:3)
#> [[1]]
#> + 3/10 vertices, from d31eb30:
#> [1] 1 2 10
#>
#> [[2]]
#> + 3/10 vertices, from d31eb30:
#> [1] 2 1 3
#>
#> [[3]]
#> + 3/10 vertices, from d31eb30:
#> [1] 3 2 4
#>
neighborhood(g, order = 2, 1:3)
#> [[1]]
#> + 5/10 vertices, from d31eb30:
#> [1] 1 2 10 3 9
#>
#> [[2]]
#> + 5/10 vertices, from d31eb30:
#> [1] 2 1 3 10 4
#>
#> [[3]]
#> + 5/10 vertices, from d31eb30:
#> [1] 3 2 4 1 5
#>
# attributes are preserved
V(g)$name <- c("a", "b", "c", "d", "e", "f", "g", "h", "i", "j")
make_ego_graph(g, order = 2, 1:3)
#> [[1]]
#> IGRAPH 6f7aced UN-- 5 4 -- Ring graph
#> + attr: name (g/c), mutual (g/l), circular (g/l), name (v/c)
#> + edges from 6f7aced (vertex names):
#> [1] a--b b--c a--j i--j
#>
#> [[2]]
#> IGRAPH 40d9320 UN-- 5 4 -- Ring graph
#> + attr: name (g/c), mutual (g/l), circular (g/l), name (v/c)
#> + edges from 40d9320 (vertex names):
#> [1] a--b b--c c--d a--j
#>
#> [[3]]
#> IGRAPH 9f66da1 UN-- 5 4 -- Ring graph
#> + attr: name (g/c), mutual (g/l), circular (g/l), name (v/c)
#> + edges from 9f66da1 (vertex names):
#> [1] a--b b--c c--d d--e
#>
# make_neighborhood_graph() is an alias of make_ego_graph()
make_neighborhood_graph(g, order = 2, 1:3)
#> [[1]]
#> IGRAPH 31dfd85 UN-- 5 4 -- Ring graph
#> + attr: name (g/c), mutual (g/l), circular (g/l), name (v/c)
#> + edges from 31dfd85 (vertex names):
#> [1] a--b b--c a--j i--j
#>
#> [[2]]
#> IGRAPH 8be819e UN-- 5 4 -- Ring graph
#> + attr: name (g/c), mutual (g/l), circular (g/l), name (v/c)
#> + edges from 8be819e (vertex names):
#> [1] a--b b--c c--d a--j
#>
#> [[3]]
#> IGRAPH 609bec4 UN-- 5 4 -- Ring graph
#> + attr: name (g/c), mutual (g/l), circular (g/l), name (v/c)
#> + edges from 609bec4 (vertex names):
#> [1] a--b b--c c--d d--e
#>
# connecting to the neighborhood
g <- make_ring(10)
g <- connect(g, 2)