为 seaborn 热图添加阴影

Question

有没有办法在 seaborn 热图中孵化特定的“细胞”，例如满足条件？ 我已经用掩码数组和 matplotlib pcolor 尝试过，但结果是它孵化了错误的单元格。

import numpy as np
import seaborn as sns
import matplotlib.pyplot as plt

flights = sns.load_dataset("flights")
flights = flights.pivot("month", "year", "passengers")
zm = np.ma.masked_less(flights.values, 200)
x= np.arange(0,12)
y= np.arange(0,12)
sns.heatmap(flights,linewidth=.1)
plt.pcolor(x, y, zm, hatch='//', alpha=0.)

plt.show()

Answer 1

我认为这个想法/策略是正确的。你只是没有使用正确的坐标。

import numpy as np
import seaborn as sns
import matplotlib.pyplot as plt

flights = sns.load_dataset("flights")
flights = flights.pivot("month", "year", "passengers")
print(flights)
zm = np.ma.masked_less(flights.values, 200)
x= np.arange(len(flights.columns)+1)
y= np.arange(len(flights.index)+1)
sns.heatmap(flights,linewidth=.1)
plt.pcolor(x, y, zm, hatch='//', alpha=0.)

plt.show()

您可能想要孵化单个单元格，而不是整个区域。这很难。一个解决方法是创建一个小刻度网格并将其着色为白色以覆盖阴影。

import numpy as np
import seaborn as sns
import matplotlib.pyplot as plt

plt.rcParams["axes.axisbelow"] = False

flights = sns.load_dataset("flights")
flights = flights.pivot("month", "year", "passengers")

zm = np.ma.masked_less(flights.values, 200)
x= np.arange(len(flights.columns)+1)
y= np.arange(len(flights.index)+1)

fig, ax = plt.subplots()
sns.heatmap(flights,linewidth=0, ax=ax)

ax.pcolor(x, y, zm, hatch='//', alpha=0.)

ax.set_xticks(np.arange(flights.shape[1]+1), minor=True)
ax.set_yticks(np.arange(flights.shape[1]+1), minor=True)
ax.grid(True, which="minor", color="w", linewidth=2)
ax.tick_params(which="minor", left=False, bottom=False)

plt.show()