将 igraph 对象布局为扇形 [R]

Question

我有一个分层的 non-binary 树结构，表示为 igraph 对象。

library(igraph)
df = data.frame(subregion = c("Africa", "Europe", "Asia", "Namibia", "Kenya", "Egypt", "Belgium", "China", "India"),
       region = c("World", "World", "World", "Africa", "Africa", "Africa", "Europe", "Asia", "Asia"))
df_graph = graph_from_data_frame(df, directed = F)
plot(df_graph, layout = layout_as_tree(df_graph, root = "World"))

共有三个层级，同一层级的节点同样不同。现在我想将此图布局为扇形，就像您可以使用树状图一样：

df_graph_cl = cluster_fast_greedy(df_graph)
plot_dendrogram(df_graph_cl, type = "fan")

但是，树状图中未保留节点之间的原始关系，因为它是二元树。关于如何将图形布局为扇形而不将其转换为树状图，有什么想法吗？

Answer 1

我现在想出了一个解决方法，我想我会分享它。关键是将图形转换为 NEWICK format. For that, I had to write a little function，对图形执行深度优先搜索并创建 NEWICK 字符串。

使用示例数据，我现在可以轻松做到：

library(phytools)
newick = graph_to_newick(df_graph, root = "World")
df_tree = collapse.singles(read.newick(text = newick))
plot(df_tree, type = "fan")

产生所需的输出：

将 igraph 对象布局为扇形 [R]

Layout igraph object as fan [R]

r

igraph