填充曲线和对角线之间的区域

Question

你能帮我解决这个问题吗？ 我想知道如何填充曲线和对角线（连接 (X min, Y min) 到 (X max, Y max) 的线）之间的区域。例如，在下面的图中，我们如何填充上面的区域对角线为红色，下方区域为蓝色。提前请您花时间考虑。

import numpy as np
import matplotlib.pyplot as plt

fig, ax = plt.subplots(figsize = (6,4))
x=np.array([0,1,2,3,4,5,6,7,8,9,10])
y=np.array([0,4,5,5,4,5,6,8,9,9,15])

ax.plot(x,y, color = "red", lw=1.2)
ax.plot([x.min(),x.max()],[y.min(),y.max()], color = "black", lw=1.2)

plt.show()

Answer 1

谢谢你。我能做到这一点。我用 [x.min(),x.max()],[y.min(),y.max()] 拟合了一个线性回归模型来定义对角线，然后用对角线。

import numpy as np
from sklearn.linear_model import LinearRegression
import matplotlib.pyplot as plt

fig, ax = plt.subplots(figsize = (6,4))
x=np.array([0,1,2,3,4,5,6,7,8,9,10])
y=np.array([0,4,5,5,4,5,6,8,9,9,15])

ax.plot(x,y, color = "red", lw=1.2)
(m,b)=np.polyfit([x.min(),x.max()] ,[y.min(),y.max()] ,1)
yp = np.polyval([m,b],x)
plt.plot(x,yp, color='black',lw=1)
ax.fill_between(x,y, yp, where=(y > yp), color='red',interpolate=True)
ax.fill_between(x, y, yp, where=(y <= yp), color='blue',interpolate=True)
plt.show()

Answer 2

fill_between() 方法是专门为此设计的：

# Create empty figure 
_,ax = plt.subplots()
# Plot the two lines
ax.plot(x,x,color='C0')
ax.plot(x,y,color='C3')
# Plot the area with two conditions (x>y) and (x<=y)
ax.fill_between(x, x, y, where=(x > y), color='C0', alpha=0.2,
                 interpolate=True)
ax.fill_between(x, x, y, where=(x <= y), color='C3', alpha=0.2,
                 interpolate=True)

我们得到：