`subgraph`

creates a subgraph of a graph, containing only the specified
vertices and all the edges among them.

`subgraph(graph, v)`induced_subgraph(
graph,
vids,
impl = c("auto", "copy_and_delete", "create_from_scratch")
)

subgraph.edges(graph, eids, delete.vertices = TRUE)

graph

The original graph.

v

Numeric vector, the vertices of the original graph which will form the subgraph.

vids

Numeric vector, the vertices of the original graph which will form the subgraph.

impl

Character scalar, to choose between two implementation of the
subgraph calculation. ‘`copy_and_delete`

’ copies the graph
first, and then deletes the vertices and edges that are not included in the
result graph. ‘`create_from_scratch`

’ searches for all vertices
and edges that must be kept and then uses them to create the graph from
scratch. ‘`auto`

’ chooses between the two implementations
automatically, using heuristics based on the size of the original and the
result graph.

eids

The edge ids of the edges that will be kept in the result graph.

delete.vertices

Logical scalar, whether to remove vertices that do
not have any adjacent edges in `eids`

.

A new graph object.

`induced_subgraph`

calculates the induced subgraph of a set of vertices
in a graph. This means that exactly the specified vertices and all the edges
between them will be kept in the result graph.

`subgraph.edges`

calculates the subgraph of a graph. For this function
one can specify the vertices and edges to keep. This function will be
renamed to `subgraph`

in the next major version of igraph.

The `subgraph`

function does the same as `induced.graph`

currently
(assuming ‘`auto`

’ as the `impl`

argument), but it is
deprecated and will be removed in the next major version of igraph.

```
# NOT RUN {
g <- make_ring(10)
g2 <- induced_subgraph(g, 1:7)
g3 <- subgraph.edges(g, 1:5, 1:5)
# }
```

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