Python matplotlib:图例不从networkx图形继承节点颜色

我在Windows7上使用Python 2.7运行matplotlib v1.4.3。当我使用networkx生成图形时，通过node_color参数传递的节点颜色不会被图例继承。图例的圆圈是默认的蓝色。下面的代码是显示问题的测试用例。我是SO的新用户，无法发布图像，但您可以复制/粘贴代码以查看问题

import networkx as nx
import matplotlib.pyplot as plt
import numpy as np

# define nodes, node types, and color range
np.random.seed(10000)
nodes = list('abcdefghijkl')
nodeTypes = ['foo','bar','baz']
nodeColors = [0.0, 0.5, 1.0]

# assign each node a type and color via a dictionaries
nodeTypeDict = dict(zip(nodeTypes, [nodes[:4],nodes[4:8],nodes[8:]]))
nodeColorDict = dict(zip(nodeTypes, nodeColors))
nodePos = dict(zip(nodes,[(np.random.random(),np.random.random()) 
                                        for i in range(len(nodes))]))

# generate the graph
g = nx.Graph()
g.add_nodes_from(nodes)

# create image canvas and axes
fig, ax = plt.subplots(1, figsize=(6,6))

# iterate each nodetype, changing colors and labels of the nodes
for nt in nodeTypes:
    # choose nodes and color for each iteration
    nlist = nodeTypeDict[nt]
    ncolor = [nodeColorDict[nt]]*len(nlist)
    # draw the graph
    nx.draw_networkx_nodes(g, 
                           pos=nodePos,
                           nodelist=nlist,
                           ax=ax, 
                           cmap=plt.cm.brg, 
                           vmin=0.0,
                           vmax=1.0,
                           node_color=ncolor,
                           label=nt)  # the label for each iteration is 
                                      # the node type

# here is the problem.  The legend does not inherit the colors.
ax.legend(scatterpoints=1)
plt.show()

---

这是一个有效的版本

import networkx as nx
import matplotlib.pyplot as plt
import numpy as np

# define nodes, node types, and color range
np.random.seed(10000)
nodes = list('abcdefghijkl')
nodeTypes = ['foo','bar','baz']
nodeColors = ['r', 'b', 'k']

# assign each node a type and color via a dictionaries
nodeTypeDict = dict(zip(nodeTypes, [nodes[:4],nodes[4:8],nodes[8:]]))
nodeColorDict = dict(zip(nodeTypes, nodeColors))
nodePos = dict(zip(nodes,[(np.random.random(),np.random.random()) 
                                        for i in range(len(nodes))]))

# generate the graph
g = nx.Graph()
g.add_nodes_from(nodes)

# create image canvas and axes
fig, ax = plt.subplots(1, figsize=(6,6))

# iterate each nodetype, changing colors and labels of the nodes
for nt in nodeTypes:
    # choose nodes and color for each iteration
    nlist = nodeTypeDict[nt]
    ncolor = nodeColorDict[nt]
    print ncolor
    # draw the graph
    nx.draw_networkx_nodes(g, 
                           pos=nodePos,
                           nodelist=nlist,
                           ax=ax, 
                           node_color=ncolor,
                           label=nt)  # the label for each iteration is 
                                      # the node type

# here is the problem.  The legend does not inherit the colors.
ax.legend(scatterpoints=1)
plt.savefig('tmp.png')

我以为我能很快解释出什么地方出了问题，但我真的不知道。首先-如果要使特定命令的所有颜色相同，则无需将颜色列表发送到

draw\u networkx\u节点

。把它换成单色就行了。我原以为这样可以解决问题，但后来我在cmap上遇到了麻烦。然后我明确说明了使用什么颜色，问题就解决了

---

所以-我得到的效果很好，当它绘制图例时，它似乎没有得到颜色映射编码的正确颜色。我建议在调用

draw\u networkx\u nodes

之前先确定颜色，然后发送颜色即可。

谢谢。这很有帮助。看起来color_节点只希望来自cmap的RGB而不是RGBa能够传递到图例。我在nodeColorsIndex中为nci添加了

nodeColorsIndex=[0.0,0.5,1.0]

和

nodeColors=[colmap（nci）[0:3]

，效果非常好。是的，我只是在玩它，发现问题是它需要长度为3。我仍然很难弄清楚如何让它尊重vmin和vmax参数。如果对你有用的话，我现在就把它留下。