三级饼图 matplotlib - 如何“美化”

Question

我试图在 matplotlib 中模拟一个三级饼图，但对它的美感不满意。

具体来说，我似乎无法让三个级别（或甜甜圈）更具特色。另外，我想理想地将标签显示为图例，而不是它们当前的显示方式。最后，如果可能的话，我希望能有一套互补的 8 种颜色。

我的代码如下：

import matplotlib.pyplot as plt
import numpy as np

first_labels = ["B", "S", "D", "SG", "OBGL", "G", 'T', "O", "I"]
first_sizes = [2000, 300, 200, 100, 100, 150, 40, 30, 700]

second_sizes = [1000, 200, 200, 400, 500, 40, 1, 1, 1000]

third_sizes = [500, 300, 400, 500, 400, 100, 5, 2, 800]

flatui = (sns.diverging_palette(20, 250, n=8))


bigger = plt.pie(first_sizes, labels=first_labels, colors=flatui,
                 startangle=90, frame=True, radius = 1)


smaller = plt.pie(second_sizes,
                  colors=flatui, radius=0.9,
                  startangle=90, labeldistance=0.9)



smallest = plt.pie(third_sizes,
                  colors=flatui, radius=0.8,
                  startangle=90, labeldistance=0.8)


centre_circle = plt.Circle((0, 0), 0.7, color='white', linewidth=0)


fig = plt.gcf()
fig.gca().add_artist(centre_circle)

plt.axis('equal')
plt.tight_layout()

plt.show()

有人可以建议如何“美化”饼图吗？

Answer 1

来自documentation of plt.pie 和this page：

[...]
wedgeprops : dict, optional, default: None
Dict of arguments passed to the wedge objects making the pie. For example, you can pass in wedgeprops = {'linewidth': 3} to set the
width of the wedge border lines equal to 3. For more details, look at
the doc/arguments of the wedge object. By default clip_on=False.
[...]

您可以通过将名为 wedgeprops 的字典输入到您的饼图中来自定义楔形。例如：

[...] repeating your code [...]

bigger = plt.pie(first_sizes, labels=first_labels, colors=flatui,
                 startangle=90, frame=True, radius = 1,
                wedgeprops={'edgecolor':'k'})


smaller = plt.pie(second_sizes,
                  colors=flatui, radius=0.9,
                  startangle=90, labeldistance=0.9,
                 wedgeprops={'edgecolor':'k'})



smallest = plt.pie(third_sizes,
                  colors=flatui, radius=0.8,
                  startangle=90, labeldistance=0.8,
                  wedgeprops={'edgecolor':'k'})

centre_circle = plt.Circle((0, 0), 0.7, color='white', linewidth=0)

fig = plt.gcf()
fig.gca().add_artist(centre_circle)

# add legend to current ax:
plt.gca().legend(loc='center right', bbox_to_anchor=(1,0,0.5,0.5))

如果您只想要图例中的标签而不是情节：

# make first pie without labels:
bigger = plt.pie(first_sizes, colors=flatui,
                 startangle=90, frame=True, radius = 1,
                wedgeprops={'edgecolor':'k'})

# feed labels to legend:
plt.gca().legend(first_labels, loc='center right', bbox_to_anchor=(1,0,0.5,0.5))