向嵌套饼图添加图例

Question

我想在嵌套饼图的内部饼图中添加图例：

import matplotlib.pyplot as plt

# Make data: I have 3 groups and 7 subgroups
group_names=['groupA', 'groupB', 'groupC']
group_size=[12,11,30]
subgroup_names=['A.1', 'A.2', 'A.3', 'B.1', 'B.2', 'C.1', 'C.2', 'C.3', 
'C.4', 'C.5']
subgroup_size=[4,3,5,6,5,10,5,5,4,6]

# Create colors
a, b, c=[plt.cm.Blues, plt.cm.Reds, plt.cm.Greens]

# First Ring (outside)
fig, ax = plt.subplots()
ax.axis('equal')
mypie, _ = ax.pie(group_size, radius=1.3, labels=group_names, colors= 
[a(0.6), b(0.6), c(0.6)] )
plt.setp( mypie, width=0.3, edgecolor='white')

# Second Ring (Inside)
mypie2, _ = ax.pie(subgroup_size, radius=1.3-0.3, 
labels=subgroup_names, labeldistance=0.7, colors=[a(0.5), a(0.4), 
a(0.3), b(0.5), b(0.4), c(0.6), c(0.5), c(0.4), c(0.3), c(0.2)])
plt.setp( mypie2, width=0.4, edgecolor='white')
plt.margins(0,0)

subgroup_names_legs=['A.1:a1desc', 'A.2:a2desc', 'A.3:a3desc', 
'B.1:b1desc', 'B.2:b2desc', 'C.1:c1desc', 'C.2:c2desc', 'C.3:c3desc', 
'C.4:c4desc', 'C.5:c5desc']
plt.legend(subgroup_names_legs,loc='best')

# show it
plt.show()

所以我得到了这个结果：

我想在图例中正确引用颜色（例如，A1、A2 和 A3 是不同种类的蓝色等）

此外，如何以不与图表重叠的方式显示图例？

Answer 1

问题是您首先使用 labels=subgroup_names 分配图例，然后使用 plt.legend(subgroup_names_legs,loc='best') 重新分配它们。因此，您正在覆盖现有值并因此破坏了顺序这就是您看到不匹配颜色的原因。

为避免图例框与图形重叠，您可以将其位置指定为loc=(0.9, 0.1)

要摆脱外部饼图的图例，您可以抓住图例句柄和标签，然后排除前三个条目，这样您就只有内部饼图的图例

# First Ring (outside)
fig, ax = plt.subplots()
ax.axis('equal')
mypie, _ = ax.pie(group_size, radius=1.3, labels=group_names, colors= 
[a(0.6), b(0.6), c(0.6)] )
plt.setp( mypie, width=0.3, edgecolor='white')

# Second Ring (Inside)
mypie2, _ = ax.pie(subgroup_size, radius=1.3-0.3, 
labels=subgroup_names, labeldistance=0.7, colors=[a(0.5), a(0.4), 
a(0.3), b(0.5), b(0.4), c(0.6), c(0.5), c(0.4), c(0.3), c(0.2)])
plt.setp( mypie2, width=0.4, edgecolor='white')
plt.margins(0,0)

plt.legend(loc=(0.9, 0.1))
handles, labels = ax.get_legend_handles_labels()

ax.legend(handles[3:], subgroup_names_legs, loc=(0.9, 0.1))
plt.show()

向嵌套饼图添加图例

Add legends to nested pie charts

python

matplotlib

legend-properties

pie-chart