检查python中networkx中是否存在具有相同标签的节点

Question

我使用以下代码使用networkx构建我的图形,如下所示.

mylist = [('chocolate_pudding', 6.3), ('tim_tam', 178.5), ('bread', 3.5), 
('chocolate_pudding', 8.5), ('tim_tam', 3.0), ('butter', 204.0)]

G = nx.Graph()

for ele in mylist:
    #if node with ele[0] does not exists, add the new node
         G.add_node(ele[0], weight=ele[1])
    #else, update the weight with the new weight value (weight = existing_weight + ele[1])

我想在创建新节点之前检查具有相同标签的节点是否存在.如果节点存在,我想通过将新值添加到现有值来更新其权重.

例如,在上面的例子中,我只想要4个节点chocolate_pudding, tim_tam, bread, butter,它们的权重应14.8, 181.5, 3.5, 204.0分别为.

我没有找到在networkx中这样做的正确方法.因此,请告诉我是否可以在networkx中进行此操作？

Answer 1

您可以ele[0] in G用来检查标签ele[0]是否已经存在.更新值非常简单.

import networkx as nx
mylist = [('chocolate_pudding', 6.3), ('tim_tam', 178.5), ('bread', 3.5), ('chocolate_pudding', 8.5), ('tim_tam', 3.0), ('butter', 204.0)]

G = nx.Graph()

for ele in mylist: 
     if ele[0] not in G:
         G.add_node(ele[0], weight=ele[1])
     else:
         new_weight = G.nodes[ele[0]]["weight"] + ele[1]
         # set values
         G.node[ele[0]]["weight"] = new_weight

G.nodes(data=True)        
# NodeDataView({'chocolate_pudding': {'weight': 14.8}, 
#               'tim_tam': {'weight': 181.5}, 
#               'bread': {'weight': 3.5}, 
#               'butter': {'weight': 204.0}})

编辑:此答案基于networkx 2.0.似乎在networkx 2.0之前,nodes它只是一个函数而不是一个属性.因此,您可能需要参考文档以了解如何更新节点.我的猜测G.nodes(data=True)[ele[0]]["weight] = new_weight会起作用.或结账set_node_attributes功能.