python - 使边从 Networkx 中的节点外部开始

Question

我有一个加权圆形布局图。
我想让边缘从节点的外部开始，但找不到这样做的方法。我尝试设置 alpha=1，但这并没有给我想要的结果。
下图显示了我现在得到的

这是我现在对节点的以下代码:

for n in G.nodes():
    if n in set1:
        G.nodes[n]['color'] = '#7a8eff'
    elif n in set2:
        G.nodes[n]['color'] = '#eb2c30'
    elif n in set3:
        G.nodes[n]['color'] = '#7300ff'
    else:
        G.nodes[n]['color'] = '#730a15'

colors = [node[1]['color'] for node in G.nodes(data=True)]
nx.draw_networkx_nodes(G, pos, node_size=1000, node_color=colors)


# edges
for edge in G.edges():
    source, target = edge
    rad = 0.25
    node_color_dict = dict(G.nodes(data='color'))
    if node_color_dict[source] == node_color_dict[target]:
        arrowprops=dict(lw=G.edges[(source,target)]['weight'],
                        arrowstyle="-",
                        color='blue',
                        connectionstyle=f"arc3,rad={rad}",
                        linestyle= '-',
                        alpha=0.45)
        ax.annotate("",
                    xy=pos[source],
                    xytext=pos[target],
                    arrowprops=arrowprops
                   )
    else:
        arrowprops=dict(lw=G.edges[(source,target)]['weight'],
                        arrowstyle="-",
                        color='purple',
                        connectionstyle=f"arc3,rad={rad}",
                        linestyle= '-',
                        alpha=0.45)
        ax.annotate("",
                    xy=pos[source],
                    xytext=pos[target],
                    arrowprops=arrowprops
                   )
# labels
nx.draw_networkx_labels(G, pos, font_size=11, font_family="monospace", font_color='white', font_weight='bold', alpha=1.0)

Answer 1

一个完整的例子，它产生了想要的结果:

import networkx as nx
import matplotlib.pylab as pl


G = nx.karate_club_graph()
pos = nx.kamada_kawai_layout(G)

set1 = set(node for node in G if G.nodes[node]["club"] == "Mr. Hi")
set2 = set(node for node in G if G.nodes[node]["club"] != "Mr. Hi")

for n in G.nodes():
    if n in set1:
        G.nodes[n]['color'] = '#7a8eff'
    elif n in set2:
        G.nodes[n]['color'] = '#eb2c30'

for u, v in G.edges():
    G.edges[(u,v)]["weight"] = 1

colors = [node[1]['color'] for node in G.nodes(data=True)]
nodes_draw = nx.draw_networkx_nodes(G, pos, node_size=1000, node_color=colors)

ax = pl.gca()

# draw in the order, edges, nodes, node labels
zorder_edges = 3
zorder_nodes = 4
zorder_node_labels = 5

# edges
for edge in G.edges():
    source, target = edge
    rad = 0.25
    node_color_dict = dict(G.nodes(data='color'))
    if node_color_dict[source] == node_color_dict[target]:
        arrowprops=dict(lw=G.edges[(source,target)]['weight'],
                        arrowstyle="-",
                        color='blue',
                        connectionstyle=f"arc3,rad={rad}",
                        linestyle= '-',
                        #alpha=0.45,
                        zorder=zorder_edges,
                        )
        ax.annotate("",
                    xy=pos[source],
                    xytext=pos[target],
                    arrowprops=arrowprops
                   )
    else:
        arrowprops=dict(lw=G.edges[(source,target)]['weight'],
                        arrowstyle="-",
                        color='purple',
                        connectionstyle=f"arc3,rad={rad}",
                        linestyle= '-',
                        #alpha=0.45,
                        zorder=zorder_edges,
                        )
        ax.annotate("",
                    xy=pos[source],
                    xytext=pos[target],
                    arrowprops=arrowprops
                   )
# labels
node_labels_dict = nx.draw_networkx_labels(G, pos, font_size=11, font_family="monospace", font_color='white', font_weight='bold',
                                           #alpha=1.0
                                           )

nodes_draw.set_zorder(zorder_nodes)
for node_labels_draw in node_labels_dict.values():
    node_labels_draw.set_zorder(zorder_node_labels)

pl.axis("off")
# do don't cut off nodes
ax.set_xlim([1.1*x for x in ax.get_xlim()])
ax.set_ylim([1.1*y for y in ax.get_ylim()])
pl.show()

结果:

背景
您可以更改 zorder 创建的 matplotlib对象:

import networkx as nx
import matplotlib.pylab as pl
# an example graph with string (names) as nodes
g = nx.karate_club_graph()
pos = nx.kamada_kawai_layout(g)

e = nx.draw_networkx_edges(g, pos=pos, )
n = nx.draw_networkx_nodes(g, pos=pos, )

e.set_zorder(5) 
n.set_zorder(10)
pl.show()

如果您使用一些高级边缘绘制，请添加 zorder all possible parameters 的箭头 Prop 参数 ( annotate ) 的参数，例如

arrowprops=dict(lw=G.edges[(source,target)]['weight'],
                        arrowstyle="-",
                        color='blue',
                        connectionstyle=f"arc3,rad={rad}",
                        linestyle= '-',
                        alpha=0.45,
                        zorder=0)

我已包含 this answer避免在边界处切割节点。