plot_node_degrees: Visualize Node Degree Distribution in a Network Graph

In ig.degree.betweenness: "Node+Edge Betweenness Community Detection Algorithm for 'igraph' Objects"

Visualize Node Degree Distribution in a Network Graph

Description

Generates a horizontal bar‐style plot of node degrees for an igraph network. For undirected graphs, it shows each node’s total degree. For directed graphs, it displays in‐degrees (as negative bars) alongside out‐degrees.

Usage

plot_node_degrees(graph)

Arguments

graph

An igraph object. Can be either directed or undirected.

Details

This function computes:

Total degree

Number of edges incident on each node (for undirected graphs).

In‐degree

Number of incoming edges per node (for directed graphs).

Out‐degree

Number of outgoing edges per node (for directed graphs).

For directed graphs, in‐degrees are negated so that bars extend leftward, providing an immediate visual comparison to out‐degrees.

Internally, it uses:

• igraph::degree() to compute degrees,

• dplyr and tidyr for reshaping the data,

• ggplot2 for plotting.

Value

A ggplot object:

• Undirected graphs: A bar for each node showing its total degree.

• Directed graphs: Split bars per node with negative values for in‐degree (pointing left) and positive values for out‐degree (pointing right).

Customization

You can modify the returned ggplot with additional layers, themes, or labels. For example, to add a title or change colors:

plot_node_degrees(g) +
  ggtitle("Degree Distribution") +
  scale_fill_manual(values = c("in_degree" = "steelblue", "out_degree" = "salmon"))

Examples

library(ig.degree.betweenness)
library(igraphdata)
data("karate")
data("oncology_network")
plot_node_degrees(oncology_network)
plot_node_degrees(karate)

ig.degree.betweenness documentation built on June 18, 2026, 1:06 a.m.