network (version 1.0-1)

attribute.methods: Attribute Interface Methods for the Network Class

Description

These methods get, set, list, and delete attributes at the network, edge, and vertex level.

Usage

delete.edge.attribute(x, attrname)
delete.network.attribute(x, attrname)
delete.vertex.attribute(x, attrname)
get.edge.attribute(el, attrname, unlist = TRUE)
get.edge.value(x, attrname, unlist = TRUE)
get.network.attribute(x, attrname, unlist = FALSE)
get.vertex.attribute(x, attrname, na.omit = FALSE, null.na = TRUE,
    unlist = TRUE)
network.vertex.names(x)
list.network.attributes(x)
list.edge.attributes(x)
list.vertex.attributes(x)
set.edge.attribute(x, attrname, value, e=1:length(x$mel))
set.edge.value(x, attrname, value, e=1:length(x$mel))
set.network.attribute(x, attrname, value)
set.vertex.attribute(x, attrname, value, v=1:network.size(x))

Arguments

el

a list of edges (possibly network$mel).

x

an object of class network.

attrname

the name of the attribute to get or set.

unlist

logical; should retrieved attributes be unlisted prior to being returned?

na.omit

logical; should values from missing vertices/edges be removed?

null.na

logical; should NULL values be replaced with NAs?

value

values of the attribute to be set; these should be in vector or list form for the edge and vertex cases, or matrix form for set.edge.value.

e

IDs for the edges whose attributes are to be altered.

v

IDs for the vertices whose attributes are to be altered.

Value

• For the list.attributes methods, a vector containing attribute names. For the get.attribute methods, a list containing the values of the attribute in question (or simply the value itself, for get.network.attribute). For the set.attribute and delete.attribute methods, a pointer to the updated network object.

Details

The list.attributes functions return the names of all edge, network, or vertex attributes (respectively) in the network. All attributes need not be defined for all elements; the union of all extant attributes for the respective element type is returned.

The get.attribute functions look for an edge, network, or vertex attribute (respectively) with the name attrname, returning its values. Note that, to retrieve an edge attribute from all edges within a network x, x$mel should be used as the first argument to get.edge.attribute; get.edge.value is a convenience function which does this automatically. network.vertex.names is a convenience function to extract the "vertex.names" attribute from all vertices.

The set.attribute functions allow one to set the values of edge, network, or vertex attributes. set.edge.value is a convenience function which allows edge attributes to be given in adjacency matrix form. The delete.attribute functions, by contrast, remove the named attribute from the network, from all edges, or from all vertices (as appropriate). If attrname is a vector of attribute names, each will be removed in turn. These functions modify their arguments in place, although a pointer to the modified object is also (invisibly) returned.

Note that some attribute assignment/extraction can be performed through the various extraction/replacement operators. See the associated man page for details.

References

Butts, C.T. 2002. ``Memory Structures for Relational Data in R: Classes and Interfaces'' Working Paper.

See Also

network, as.network.matrix, as.sociomatrix, as.matrix.network, network.extraction

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)

#Create a matrix of values corresponding to edges
mm<-m
mm[1,2]<-7; mm[2,3]<-4; mm[3,1]<-2

#Assign some attributes
set.edge.attribute(g,"myeval",3:5)
set.edge.value(g,"myeval2",mm)
set.network.attribute(g,"mygval","boo")
set.vertex.attribute(g,"myvval",letters[1:3])

#List the attributes
list.edge.attributes(g)
list.network.attributes(g)
list.vertex.attributes(g)

#Retrieve the attributes
get.edge.attribute(g$mel,"myeval")  #Note the first argument!
get.edge.value(g,"myeval")          #Another way to do this
get.edge.attribute(g$mel,"myeval2") 
get.network.attribute(g,"mygval")
get.vertex.attribute(g,"myvval")

#Purge the attributes
delete.edge.attribute(g,"myeval")
delete.edge.attribute(g,"myeval2")
delete.network.attribute(g,"mygval")
delete.vertex.attribute(g,"myvval")

#Verify that the attributes are gone
list.edge.attributes(g)
list.network.attributes(g)
list.vertex.attributes(g)

#Note that we can do similar things using operators
g %n% "mygval" <- "boo"               #Set attributes, as above
g %v% "myvval" <- letters[1:3]
g %e% "myeval" <- mm
g[,,names.eval="myeval"] <- mm          #Another way to do this
g %n% "mygval"                        #Retrieve the attributes
g %v% "myvval"
g %e% "mevval"
as.sociomatrix(g,"myeval")              # Or like this