matplotlib 中的 barplot 中的 fill_between()

Question

import matplotlib.pyplot as plt

# define corner points
x=['a','b','c','d','e']
y=[12,10,5,1,4]
plt.bar(x,y,color='lightgray')
plt.fill_between(x,3,alpha=0.3,color='r')

I'd like to fill the empty space using fill_between() as shown in the picture.

Answer 1

You can use axhspan to have a horizontal bar over the complete plot width. Use zorder to have it behind the bars.

import matplotlib.pyplot as plt

x = ['a', 'b', 'c', 'd', 'e']
y = [12, 10, 5, 1, 4]
plt.bar(x, y, color='lightgray')
plt.axhspan(0, 3, alpha=0.3, color='r', zorder=0)
plt.show()

PS: Note that the call to fill_between in the post doesn't fill between the bars. It converts the x-values to numeric (being 0, 1, 2, ... for a categorical axis) and uses a default y2=0 . So, internally equal to:

plt.fill_between(x=[0, 1, 2, 3, 4], y1=3, y2=0, ...)