向节点，边和图添加属性

Question

I am a new user of python and networkx and I want to ask you that how to add attributes to graphs,nodes and edges in networkx ?When I try to add it there is an error Traceback (most recent call last):

File "<pyshell#9>", line 1, in <module>
    G[1][3]['color']='blue'
KeyError: 3

I have searched for attribute package for networkx but not found.

Answer 1

Well it seems your node G[1] doesn't have four children (3 wuold be the fourth and 0 the first).

According to the python documetation:

exception KeyError
Raised when a mapping (dictionary) key is not found in the set of existing keys.

In other words G[1][3] does not exists.

If you are starting to Python, now is a good time to start to learn how to debug your code. That way you will get more tools for findout what's going on with your code.

You can start at: The Python Debugger

or check this question: Python debugging tips