I have the following code:
import networkx as nx
G1 = nx.erdos_renyi_graph(10,0.6)
allNodeCuts = nx.all_node_cuts(G1)
a = list(allNodeCuts)
for i in allNodeCuts:
print(i)
In this version of the code, print(i) does not occur. However, if I move the code a = list(allNodeCuts) after the for loop, the loop runs and elements are printed. Why does this happen?
This is probably because allNodeCuts is a generator and if you list all its elements, you "consume" it (i.e. the pointer is set to the end).
You can see this behavior in the following example:
sq = (x**2 for x in range(3))
type(sq)
# generator
for i in sq:
print(i)
# 0
# 1
# 4
If you run the loop again the generator is empty:
for i in sq:
print(i)
To be able to iterate through a generator without losing it one can create a copy with itertools.tee
from itertools import tee
sq, sq_copy = tee(x**2 for x in range(3))
list(sq)
# [0, 1, 4]
# now generator is empty because exhausted
list(sq)
# []
# copy is not consumed
list(sq_copy)
# [0, 1, 4]
Have you tried this? Convert the generator to a list, and iterate over the list
import networkx as nx
G1 = nx.erdos_renyi_graph(10,0.6)
allNodeCuts = nx.all_node_cuts(G1)
a = list(allNodeCuts)
for i in a:
print(i)
