基于已确定节点与边的NetworkX绘图报错(TypeError)修复求助

Problem Context #

You're trying to create a graph with NetworkX and Matplotlib to visualize your specified nodes and edges, but hitting a TypeError because the add_node() and add_edge() methods aren't being used correctly. Here's your original code, error message, and defined node/edge data:

Original Code #

import matplotlib.pyplot as plt
import networkx as nx
%matplotlib notebook
G = nx.Graph()
G.add_node(y[i]==1, color="blue", size=500)
G.add_node(y[i]==0, color="green", size=300)
G.add_edge(d[k,i]*w[k,i], color="green")
G.add_edge(d[i,j]*f[i,j]>0, color="blue")
nx.draw(G, with_labels=True)
plt.show()

Error Message #

TypeError Traceback (most recent call last)
<ipython-input-314-9036a4e704aa> in <module>
23 G.add_node(y[i]==1, color="blue", size=500)
24 G.add_node(y[i]==0, color="green", size=300)
---> 25 G.add_edge(d[k,i]*w[k,i], color="green")
26 G.add_edge(d[i,j]*f[i,j]>0, color="blue")
27 TypeError: add_edge() missing 1 required positional argument: 'v_of_edge'

Defined Node/Edge Data #

• Nodes (Y): Nodes with value 1 are indices 0, 1, 3, 12, 57, 59
• Edges (W): Pairs (22,0), (23,0), (24,0)
• Edges (F): Pairs (0,0), (0,1), (1,3), (3,59), (3,98), (8,51), (24,8), (25,0), (25,24), (51,8), (51,59), (57,12), (59,57)

Solution #

The core issue is misuse of NetworkX's node/edge methods:

• add_node() needs a unique node identifier (like the integer index), not a boolean condition.
• add_edge() requires two node identifiers (start and end of the edge), not a calculated value or boolean.

Here's the corrected code with step-by-step explanations:

Corrected Full Code #

import matplotlib.pyplot as plt
import networkx as nx
%matplotlib notebook

# Initialize the graph
G = nx.Graph()

# --- Add Nodes ---
# Collect all relevant nodes (Y=1 nodes + nodes from edges)
all_nodes = {0,1,3,12,57,59,22,23,24,8,25,51,98}

# Add each node with color and size attributes
for node in all_nodes:
    if node in {0,1,3,12,57,59}:  # Match Y[node] == 1
        G.add_node(node, color="blue", size=500)
    else:  # Assume Y[node] == 0 for edge-only nodes
        G.add_node(node, color="green", size=300)

# --- Add Edges ---
# Add W edges (green color)
w_edges = [(22,0), (23,0), (24,0)]
for u, v in w_edges:
    G.add_edge(u, v, color="green")

# Add F edges (blue color)
f_edges = [(0,0), (0,1), (1,3), (3,59), (3,98), (8,51),
           (24,8), (25,0), (25,24), (51,8), (51,59),
           (57,12), (59,57)]
for u, v in f_edges:
    G.add_edge(u, v, color="blue")

# --- Prepare plotting attributes ---
# Extract node colors, sizes, and edge colors from the graph
node_colors = [G.nodes[node]['color'] for node in G.nodes]
node_sizes = [G.nodes[node]['size'] for node in G.nodes]
edge_colors = [G.edges[edge]['color'] for edge in G.edges]

# --- Draw and display the graph ---
nx.draw(G, with_labels=True, node_color=node_colors, node_size=node_sizes, edge_color=edge_colors)
plt.show()

Key Fixes Explained #

1. Node Addition: We add nodes using their actual index values (not boolean checks) and set attributes based on whether they're in your Y=1 list. We also include all nodes that appear in edges to avoid missing nodes in the plot.
2. Edge Addition: Each edge is added as a pair of node indices (u, v), which is the required format for add_edge(). We group W and F edges separately to assign their intended colors.
3. Plot Customization: We extract the node and edge attributes we set and pass them directly to nx.draw() to ensure your styling (colors, sizes) is applied correctly.

内容的提问来源于stack exchange，提问作者Dominik