有向图

使用颜色映射和不同的节点大小绘制带有定向边的图形。

边缘有不同的颜色和alphas（不透明度）。使用Matplotlib绘制。

出：

/opt/networkx/examples/drawing/plot_directed.py:42: MatplotlibDeprecationWarning: Starting from Matplotlib 3.6, colorbar() will steal space from the mappable's axes, rather than from the current axes, to place the colorbar.  To silence this warning, explicitly pass the 'ax' argument to colorbar().
  plt.colorbar(pc)

import matplotlib as mpl
import matplotlib.pyplot as plt
import networkx as nx

seed = 13648  # Seed random number generators for reproducibility
G = nx.random_k_out_graph(10, 3, 0.5, seed=seed)
pos = nx.spring_layout(G, seed=seed)

node_sizes = [3 + 10 * i for i in range(len(G))]
M = G.number_of_edges()
edge_colors = range(2, M + 2)
edge_alphas = [(5 + i) / (M + 4) for i in range(M)]
cmap = plt.cm.plasma

nodes = nx.draw_networkx_nodes(G, pos, node_size=node_sizes, node_color="indigo")
edges = nx.draw_networkx_edges(
    G,
    pos,
    node_size=node_sizes,
    arrowstyle="->",
    arrowsize=10,
    edge_color=edge_colors,
    edge_cmap=cmap,
    width=2,
)
# set alpha value for each edge
for i in range(M):
    edges[i].set_alpha(edge_alphas[i])

pc = mpl.collections.PatchCollection(edges, cmap=cmap)
pc.set_array(edge_colors)
plt.colorbar(pc)

ax = plt.gca()
ax.set_axis_off()
plt.show()