Question

Hey guys! So here's a tough one for you. I'm working on the last problem set (ps11) and I encountered a problem related to the "in" operator. Details below.

Answer 1

So I'm trying to create and add nodes to my graph based on the code attached to the problem set. The problem is: nodes that I create and should be treated as equal (those which have the same name - as defined in the Node class) are only treated equal by the "==" operator and not the "in" operator. So the hasNode() method basically does not work. Let me know if you need more clarification or actual code.

Answer 2

Can you paste the code?

Answer 3

Hmmm... this quick test seems to work http://dpaste.com/1422496/
Paste your code and we will have a look
please use a code pasting site:

- http://dpaste.com
- http://pastebin.com
- https://gist.github.com/
- http://pastie.org
- http://codepad.org
- http://ideone.com
- http://www.repl.it/

paste your code there and post the link here. select Python syntax highlighting when u paste.

Answer 4

Sorry, guys, false alarm :) It works fine with a list, it only has a problem with a set. But as far as I understand, sets are implemented using hashes so some __hash__ method need to be defined for the Nodes before putting them in sets. I guess that means that you're not supposed to store the Node objects directly in your Digraph, only corresponding strings. Am I correct?
Anyway, I made a huge detour to figure that out... :S

Answer 5

I don't recall all the details of the pset but I did have this in my graph.py and I used it in my map/graph - maybe I went where you went.
```
class SmartNode(Node):
def __hash__(self):
return int(self.name)
```