How do I use axvfill with a boolean series

Question

I have a boolean time series that I want to use to determine the parts of the plot that should be shaded.

Currently I have:

ax1.fill_between(data.ind         


        

Answer 1

You can still use fill_between, if you like. However instead of specifying the y-coordinates in data coordinates (for which it is not a priori clear, how large they need to be) you can specify them in axes coorinates. This can be achieved using a transform, where the x part is in data coordinates and the y part is in axes coordinates. The xaxis transform is such a transform. (This is not very surprising since the xaxis is always independent of the ycoorinates.) So

ax.fill_between(data.index, 0,1, where=data['USREC'], transform=ax.get_xaxis_transform())

would do the job.

Here is a complete example:

import matplotlib.pyplot as plt
import numpy as np; np.random.seed(0)

x = np.linspace(0,100,350)
y = np.cumsum(np.random.normal(size=len(x))) 
bo = np.zeros(len(y))
bo[y>5] = 1

fig, ax = plt.subplots()
ax.fill_between(x, 0, 1, where=bo, alpha=0.4, transform=ax.get_xaxis_transform())

plt.plot(x,y)
plt.show()