Networkx TypeError：输入图不是 networkx 图类型

Question

I am trying to create a directed graph using from_pandas_edgelist . I'm getting an error while passing the parameter create_using=nx.DiGraph()

1) I tried creating a directed graph object and then tried to create a graph using from_pandas_edgelist : but it creates all links as bi-directional

G=nx.DiGraph()    G=nx.from_pandas_edgelist(df_SearchRelations,source='ParentCompanyId',target='ChildCompanyId',edge_attr=True)

2) I tried creating a graph object and then converting using to_directed() , but no luck

G=nx.from_pandas_edgelist(df_SearchRelations,source='From',target='To',edge_attr=True)
G=G.to_directed()

Expected result: overcome the error of TypeError: Input graph is not a networkx graph type

PS: the same code used to work, but is suddenly failing. I am unsure if it is a version compatibility issue or an issue with the dataframe.

Answer 1

Try using create_using parameter:

G = nx.from_pandas_edgelist(df_SearchRelations,
                            source='ParentCompanyId',
                            target='ChildCompanyId',
                            edge_attr=True, 
                            create_using=nx.DiGraph())

Answer 2

I found out that the Directed graph generator will through an error when every nodes are not connected in a graph. so when we pass the edge_list as pandas dataframe, we should check whether there are any disconnected subgraphs/nodes.