Check for the existence of edge attributes in the graph

Source: R/has.R

Check for the existence of edge attributes in the graph

has_edge_attributes(x)

has_vertex_attributes(x)

has_vertex_attribute(x, attrname)

has_edge_attribute(x, attrname)

has_vertexnames(x)

has_loops(x)

has_isolates(x)

Arguments

x

graph of class igraph or network

attrname

name of the attribute to check for

Value

logical

Details

Simple utility function that returns TRUE if the graph has edge attributes and FALSE otherwise.

Functions

  • has_edge_attributes(): Check whether a graph has edge attributes

  • has_vertex_attributes(): Check whether a graph has vertex attributes (where the attribute called "na" does not count, as that is only an internal attribute by the network package)

  • has_vertex_attribute(): Check whether a graph has a specific vertex attribute (where the attribute called "na" does not count, as that is only an internal attribute by the network package)

  • has_edge_attribute(): Check whether a graph has a specific edge attribute

  • has_vertexnames(): Check whether a graph has vertex names. The function merely checks for the presence of the vertex attribute name (for a network of class igraph) or vertex.names (for a network of class network).

    Note that the network package tends to create vertex names by default, even if they were not added as separate attributes. In that case, the vertices are named as integers running from 1 to the number of vertices. Of course, this function can not distinguish whether these are names the researcher want to use as names, or purely the result of the default behavior of the network package (and not meaningful names per se).

  • has_loops(): Check whether a graph contains at least one loop (ie. an edge from a vertex to itself). Also works on a matrix.

  • has_isolates(): Check whether a graph contains at least one isolate vertex. Returns TRUE or FAlsE

Examples

data(florentine, package = "snafun")
has_vertexnames(florentine$flobusiness)      # TRUE
#> [1] TRUE

has_edge_attributes(florentine$flobusiness)  # FALSE
#> [1] FALSE
has_edge_attributes(florentine$flomarriage)  # TRUE
#> [1] TRUE

has_loops(florentine$flobusiness)
#> [1] FALSE
g <- igraph::graph( c(1,1,2,2,3,3,4,5))
has_loops(g)
#> [1] TRUE
m <- matrix(c(1, 0, 0, 0, 0, 1, 0, 1, 1), byrow = TRUE, ncol = 3)
has_loops(m)                                 # TRUE
#> [1] TRUE
diag(m) <- 0
has_loops(m)                                 # FALSE
#> [1] FALSE