# subgraph

##### Subgraph of a graph

`subgraph`

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

- Keywords
- graphs

##### Usage

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

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

##### Arguments

- 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`

.

##### Details

`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 then 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.

##### Value

A new graph object.

##### Examples

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

*Documentation reproduced from package igraph, version 1.0.1, License: GPL (>= 2)*