AttributeError：“设置”对象没有与NetworkX一起使用的属性“ number_of_nodes”

问题描述

我是NetworkX的新手，使用NetworkX 2.5，并且不赞成使用代码。该代码是从here中提取的。我尝试修复一些不推荐使用的功能，但无法使代码正常工作。我也不明白connected_components函数是如何工作的。

panama_nodes = panama.nodes()
relabel = {}

for f,cc,name in NODES:
    with open(f,encoding='utf8') as infile:
        kind = f.split(".")[0]
        data = csv.DictReader(infile)
        names_countries = {node["node_id"] :
                           (node[name].strip().upper(),node[cc])
                           for node in data
                           if node["node_id"] in panama_nodes}
    names =     {nid: values[0] for nid,values in names_countries.items()}
    countries = {nid: values[1] for nid,values in names_countries.items()}
    kinds =     {nid: kind      for nid,_      in names_countries.items()}
    nx.set_node_attributes(panama,countries,"countries")
    nx.set_node_attributes(panama,kinds,"kind")
    relabel.update(names)

nx.relabel_nodes(panama,relabel,copy=False)

if "ISSUES OF:" in panama:
    panama.remove_node("ISSUES OF:")

if "" in panama:
    panama.remove_node("")

print(nx.number_of_nodes(panama),nx.number_of_edges(panama))

components = [p.nodes() for p in nx.connected_components(panama)
              if nx.number_of_nodes(p) >= 20
              or nx.number_of_edges(p) >= 20]

panama0 = panama.subgraph(itertools.chain.from_iterable(components))

with open("panama-beneficiary.pickle","wb") as outfile:
    pickle.dump(panama0,outfile)

这些代码行返回AttributeError：

components = [p.nodes() for p in nx.connected_components(panama)
              if nx.number_of_nodes(p) >= 20
              or nx.number_of_edges(p) >= 20]

---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
<ipython-input-6-108e98bba596> in <module>
----> 1 components = [p.nodes() for p in nx.connected_components(panama)
      2               if nx.number_of_nodes(p) >= 20
      3               or nx.number_of_edges(p) >= 20]
      4 
      5 panama0 = panama.subgraph(itertools.chain.from_iterable(components))

<ipython-input-6-108e98bba596> in <listcomp>(.0)
      1 components = [p.nodes() for p in nx.connected_components(panama)
----> 2               if nx.number_of_nodes(p) >= 20
      3               or nx.number_of_edges(p) >= 20]
      4 
      5 panama0 = panama.subgraph(itertools.chain.from_iterable(components))

~\AppData\Local\Programs\Python\Python37\lib\site-packages\networkx\classes\function.py in number_of_nodes(G)
     83 def number_of_nodes(G):
     84     """Returns the number of nodes in the graph."""
---> 85     return G.number_of_nodes()
     86 
     87 

AttributeError: 'set' object has no attribute 'number_of_nodes'

感谢您的帮助！

解决方法

connected_components仅检索NetworkX 2.5中的节点集。如果我在旧版本中没有记错，它会返回子图。要调整代码，您需要执行以下操作：

components = [panama.subgraph(p).copy() for p in nx.connected_components(panama)]

# probably you want a list/set instead of a NodeView
components = [list(p.nodes()) for p in components
              if p.number_of_nodes(p) >= 20
              or p.number_of_edges(p) >= 20]

或直接

components = [p for p in nx.connected_components(panama)
              if len(p) >= 20
              or panama.subgraph(p).number_of_edges() >= 20]