Remove Elements from a Network Object

delete.edges removes one or more edges (specified by their internal ID numbers) from a network; delete.vertices performs the same task for vertices (removing all associated edges in the process).

Usage

delete.edges(x, eid, ...)

# S3 method for class 'network'
delete.edges(x, eid, ...)

delete.vertices(x, vid, ...)

# S3 method for class 'network'
delete.vertices(x, vid, ...)

Arguments

x: an object of class network.
eid: a vector of edge IDs.
...: additional arguments to methods.
vid: a vector of vertex IDs.

Value

Invisibly, a pointer to the updated network; these functions modify their arguments in place.

Details

Note that an edge's ID number corresponds to its order within x$mel. To determine edge IDs, see get.edgeIDs. Likewise, vertex ID numbers reflect the order with which vertices are listed internally (e.g., the order of x$oel and x$iel, or that used by as.matrix.network.adjacency). When vertices are removed from a network, all edges having those vertices as endpoints are removed as well. When edges are removed, the remaining edge ids are NOT permuted and NULL elements will be left on the list of edges, which may complicate some functions that require eids (such as set.edge.attribute). The function valid.eids provides a means to determine the set of valid (non-NULL) edge ids.

Edges can also be added/removed via the extraction/replacement operators. See the associated man page for details.

References

Butts, C. T. (2008). “network: a Package for Managing Relational Data in R.” Journal of Statistical Software, 24(2). doi:10.18637/jss.v024.i02

Author

Carter T. Butts buttsc@uci.edu

Examples

#Create a network with three edges
m<-matrix(0,3,3)
m[1,2]<-1; m[2,3]<-1; m[3,1]<-1
g<-network(m)

as.matrix.network(g)
#>   1 2 3
#> 1 0 1 0
#> 2 0 0 1
#> 3 1 0 0
delete.edges(g,2)              #Remove an edge
as.matrix.network(g)
#>   1 2 3
#> 1 0 0 0
#> 2 0 0 1
#> 3 1 0 0
delete.vertices(g,2)           #Remove a vertex
as.matrix.network(g)
#>   1 3
#> 1 0 0
#> 3 1 0

#Can also remove edges using extraction/replacement operators
g<-network(m)
g[1,2]<-0                      #Remove an edge
g[,]
#>   1 2 3
#> 1 0 0 0
#> 2 0 0 1
#> 3 1 0 0
g[,]<-0                        #Remove all edges
g[,]
#>   1 2 3
#> 1 0 0 0
#> 2 0 0 0
#> 3 0 0 0