nx.degree(g,i) ... what would this mean?

[rdla...@gmail.com]

I'm going through someone else's code.  It looks like the code is calling 'degree' before there are nodes initialized.  I'm wondering what is the meaning of 'degree' here, a number is returned.

import networkx as nx

. . .

g = nx.Graph()

. . .

def init_nodes():
    print "Length of g.nodes() = %d" % len(g.nodes())
    for i in range(0, len(g.nodes())):
        val = nx.degree(g, i)                                             <--- I'm not sure of what the meaning of this value returned is
                                                                                       This looks like 'degree' is being called on graph g before the graph g is constructed

        print "val=nx.degree(g,i), val=%d, i=%d" % (val,i)
        g.add_node(i,maxgrains=val, numgrains=0, active=False, fired=False)

Here's some of the output:

Length of g.nodes() = 100
val=nx.degree(g,i), val=28, i=0               <-- Values are being returned. Are these random values?
val=nx.degree(g,i), val=23, i=1
val=nx.degree(g,i), val=27, i=2
val=nx.degree(g,i), val=19, i=3
val=nx.degree(g,i), val=22, i=4

[Aric Hagberg]

It's hard to tell from your code fragments.  

If you ask for the degree of a node that doesn't exist in the graph you will get an error (not a random value).

>>> import networkx as nx

>>> G = nx.Graph()

>>> nx.degree(G,0)

'int' object is not iterableTraceback (most recent call last):

  File "<stdin>", line 1, in <module>

  File "/nh/nest/u/aric/.local/lib/python2.7/site-packages/networkx/classes/function.py", line 53, in degree

    return G.degree(nbunch,weight)

  File "/nh/nest/u/aric/.local/lib/python2.7/site-packages/networkx/classes/graph.py", line 1248, in degree

    return dict(self.degree_iter(nbunch,weight))

  File "/nh/nest/u/aric/.local/lib/python2.7/site-packages/networkx/classes/graph.py", line 1291, in degree_iter

    for n,nbrs in nodes_nbrs:

  File "/nh/nest/u/aric/.local/lib/python2.7/site-packages/networkx/classes/graph.py", line 1288, in <genexpr>

    nodes_nbrs=((n,self.adj[n]) for n in self.nbunch_iter(nbunch))

  File "/nh/nest/u/aric/.local/lib/python2.7/site-packages/networkx/classes/graph.py", line 1808, in bunch_iter

    "nbunch is not a node or a sequence of nodes.")

networkx.exception.NetworkXError: nbunch is not a node or a sequence of nodes.

Aric

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[rdla...@gmail.com]

Thanks - I think I see a code fragment that helps explain -

                            g = nx.erdos_renyi_graph(n, p)

               This statement above must initialize the graph/network g with n nodes.
and the statement
     val = nx.degree(g,i)  I think then will return the degree of the ith node of the graph g.

Let me know if that doesn't sound correct
Thanks