Question

我在图表中有一个图表g和一个节点列表subset_nodes。我想删除v_i中v_j，v_i节点v_j和subset_nodes之间的所有边缘。

我目前正在使用以下方法：

import igraph

g = igraph.Graph.Full(10)
subset_nodes = [g.vs[i] for i in range(4)]

to_delete = set()
for node in subset_nodes:
    for v in node.neighbors():
        if v in subset_nodes:
            tp = (node.index, v.index) 
            to_delete.add( tuple(sorted(tp)) )

print(len(g.es))
g.delete_edges( to_delete )
print(len(g.es))

打印：

45
39

这是有道理的，因为

10 choose 2 = 45   # total # of edges (since it is a full graph)
4 choose 2 = 6     # # of removed edges
45 - 6 = 39        # # of edges remaining

我的问题是，是否有更好，更优雅或更加pythonic的做法？

Answer 1

Igraph有＆＃34; induced_subgraph＆＃34;方法可以方便一个更简洁的解决方案：

import igraph as ig
g=ig.Graph.Full(10)
subset_nodes=[g.vs[i] for i in range(4)]
smallgraph=g.induced_subgraph(subset_nodes)
es=ig.EdgeSeq(smallgraph)
mytup=[e.tuple for e in es]
g.delete_edges(mytup)

Answer 2

另一种解决方案是：

from igraph import Graph
g = Graph.Full(10)
g.es.select(_within=range(4)).delete()

删除节点子集

2 个答案: