线程从另一个线程中断(Thread interruption from another thread)

 这里的行是说将Sender列作为源节点，将Recipient列作为Target，并将time添加为edge属性 。 因此，您只在Sender和Recipient之间创建单个（定向）边，并且只将最后一行的时间添加为边的属性。 
 
email = nx.from_pandas_dataframe(email_df, '#Sender', 'Recipient', edge_attr = 'time')
 
 您只能为一对节点定义一条边 - 您可以在构建网络之前对数据框进行分组，并将计数用作边的权重， 
 
edge_groups = email_df.groupby(["#Sender", "Recipient"], as_index=False).count().rename(columns={"time":"weight"})
email = nx.from_pandas_dataframe(edge_groups, '#Sender', 'Recipient', edge_attr = 'weight')

Your line here is saying to take the Sender column as the source node, the Recipient column as the Target and add the time as edge attributes. So you are only creating a single (directed) edge between Sender and Recipient, and only the time of the last row will be added as an attribute of the edge.
 
email = nx.from_pandas_dataframe(email_df, '#Sender', 'Recipient', edge_attr = 'time')
 
You can only have one edge defined for a pair of nodes - you could group the dataframe before constructing your network and use the count as the weights for the edges,
 
edge_groups = email_df.groupby(["#Sender", "Recipient"], as_index=False).count().rename(columns={"time":"weight"})
email = nx.from_pandas_dataframe(edge_groups, '#Sender', 'Recipient', edge_attr = 'weight')