# FAQ: Graphs: Python - Building the Graph I

This community-built FAQ covers the “Building the Graph I” exercise from the lesson “Graphs: Python”.

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Hi,

After completion of task #4, my code is returning:

{‘Grand Central Station’: <vertex.Vertex object at 0x7feef4ea6710>}

{“Grand Central Station”: grand_central}

Any idea how to display the variable name as the value? Thanks!

4 Likes

I highly suspect that it’s because our variable is a Vertex class which doesn’t have a string method?
.
I think the best way to get that result is by declaring __repr__ method inside Vertex class.
.
But I still don’t know how to convert the variable name into string as well.
hope someone can explain it better.

I managed to print the variable name to the list. the way I did it was to copy the Vertex.py code to the graph.py code and add the following repr to the vertex class.

``````  def __repr__(self):
d = [k for k,v in globals().items() if v is self]
return str(d)
``````

maybe you can do it somehow differently, but i don’t know how to debug that properly. Would love to know tho! The class is probably not part of globals because it’s in a different file. Therefore, adding the code above to vertex.py would return an index error as the variable d is empty.
here is the complete code:

``````class Vertex:
def __init__(self, value):

self.value = value
self.edges = {}

self.edges[vertex] = True

def get_edges(self):
return list(self.edges.keys())

def __repr__(self):
d = [k for k,v in globals().items() if v is self]
return str(d)

class Graph:
def __init__(self,directed = False):
self.directed = directed
self.graph_dict = {}

self.graph_dict[vertex.value] = vertex

grand_central = Vertex("Grand Central Station")

# Uncomment this code after you've defined Graph
railway = Graph()

# Uncomment these lines after you've completed .add_vertex()
print(railway.graph_dict)
print(railway.graph_dict)
``````
1 Like

I managed to get the string value by adding :

``````def __repr__(self):
return self.value
``````

in vertex.py

4 Likes

Thank you for this <3