corpustools (version 0.5.1)

ego_semnet: Create an ego network

Description

Create an ego network from an igraph object.

Usage

ego_semnet(
  g,
  vertex_names,
  depth = 1,
  only_filter_vertices = T,
  weight_attr = "weight",
  min_weight = NULL,
  top_edges = NULL,
  max_edges_level = NULL,
  directed = c("out", "in")
)

Arguments

g

an igraph object

vertex_names

a character string with the names of the ego vertices/nodes

depth

the number of degrees from the ego vertices/nodes that are included. 1 means that only the direct neighbours are included

only_filter_vertices

if True, the algorithm will only filter out vertices/nodes that are not in the ego network. If False (default) then it also filters out the edges.

weight_attr

the name of the edge attribute. if NA, no weight is used, and min_weight and top_edges are ignored

min_weight

a number indicating the minimum weight

top_edges

for each vertex within the given depth, only keep the top n edges with the strongest edge weight. Can also be a vector of the same length as the depth value, in which case a different value is used at each level: first value for level 1, second value for level 2, etc.

max_edges_level

the maximum number of edges to be added at each level of depth.

directed

if the network is directed, specify whether 'out' degrees or 'in' degrees are used

Details

The function is similar to the ego function in igraph, but with some notable differences. Firstly, if multiple vertex_names are given, the ego network for both is given in 1 network (whereas igraph creates a list of networks). Secondly, the min_weight and top_edges parameters can be used to focus on the strongest edges.

Examples

tc = create_tcorpus(c('a b c', 'd e f', 'a d'))
g = semnet(tc, 'token')

igraph::get.data.frame(g)
plot_semnet(g)
## only keep nodes directly connected to given node
g_ego = ego_semnet(g, 'e')
igraph::get.data.frame(g_ego)
plot_semnet(g_ego)

## only keep edges directly connected to given node
g_ego = ego_semnet(g, 'e', only_filter_vertices = FALSE)
igraph::get.data.frame(g_ego)
plot_semnet(g_ego)

## only keep nodes connected to given node with a specified degree (i.e. distance)
g_ego = ego_semnet(g, 'e', depth = 2)
igraph::get.data.frame(g_ego)
plot_semnet(g_ego)