python global names

Question

I'm having trouble with python. I keep getting the same error:

Traceback (most recent call last):  
  File "F:\test4", line 21, in <module>  
    graph = dict([(label, node(label))] for label in node_labels)  
  File "F:\test4", line 21, in <genexpr>  
    graph = dict([(label, node(label))] for label in node_labels)  
NameError: global name 'node' is not defined

# open network.txt and populate nodes and close file
network_file = open("network.txt", "r")
lines = [line.strip() for line in network_file]
network_file.close()
print (len(lines))


# edges which will be populated with information in network.txt
edges = []                      # list of <label, label, distance> triples
node_labels = set()             # set of node labels
graph = {}                      # dictionary of nodes keyed by labels

for line in lines:
    strNode, strNeighbor, strMetric = line.split()[:3]
    intMetric = int(strMetric)

    edges.append((strNode, strNeighbor, intMetric))
    node_labels.update([strNode, strNeighbor])

# create graph
graph = dict([(label, node(label))] for label in node_labels)

up to this line, I can't find any problem with the global variable node, it should work.

Thanks!

You're not defining a variable or function named `node` anywhere in the code you're including. *How* should it work? — Wooble, Mar 09 '11 at 15:35
node_labels is a set. graph is a dictionary. Why do you do need both for nodes? — ypercubeᵀᴹ, Mar 09 '11 at 15:54
I assumed because it is taking a number from network.txt and listing it: a = 1 b = 4 — Ranger, Mar 09 '11 at 16:09

score 2 · Answer 1 · answered Mar 09 '11 at 15:36

2

In the last line you are calling node(label). Have you defined the function node?

answered Mar 09 '11 at 15:36

dfan

5,714
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score 2 · Accepted Answer · answered Mar 09 '11 at 15:36

2

Why should it? node is nowhere defined in the code you showed... maybe you forgot an import?

answered Mar 09 '11 at 15:36

Freax

91
2

python global names

2 Answers2