即使清除后图形仍保持增长

Question

I am trying to graph two different graphs using this Python program:

K_5=nx.complete_graph(10)
print(K_5.number_of_nodes(), K_5.number_of_edges())
nx.draw(K_5)
plt.savefig('test1.png')
K_5.clear()
G = nx.Graph()
G.add_node(8)
nx.draw(G)
plt.savefig('test2.png')
print(G.number_of_nodes(), G.number_of_edges())

Which results in the following graphs:

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I have done quite a bit of digging through Stackoverflow and the matplotlib documentation, but have been unable to find anything useful. Any help would be much appreciated!

Answer 1

After you use Graph.clear() , all the nodes and edges already removed from your graph. You can check it by printing K_5.number_of_nodes() after you call Graph.clear() . However, after you plot the first figure, you don't clear it, hence, it plots on top of the first figure.

So you need to clear the matplotlib's current figure. You can use plt.clf() .

import networkx as nx
import matplotlib.pyplot as plt

K_5=nx.complete_graph(10)
print(K_5.number_of_nodes(), K_5.number_of_edges())
nx.draw(K_5)
plt.savefig('test1.png')
K_5.clear()

plt.clf() # new line, to clear the old drawings

G = nx.Graph()
G.add_node(8)
nx.draw(G)
plt.savefig('test2.png')
print(G.number_of_nodes(), G.number_of_edges())

test1.png:

test2.png: