How to set the ticks in matplotlib colorbar to be at the minimum and maximum value-CodePudding

I have a very simple plot of matplotlib.contourf like the following:

import numpy as np
import matplotlib.pyplot as plt

x = np.linspace(0, 10, 10)
y = np.linspace(0, 10, 10)
xx,yy = np.meshgrid(x,y)
X = np.array([xx,yy]).reshape(2,-1)

func_plot = X[0]   X[1]
func_plot = np.atleast_2d(func_plot).reshape(10, 10)

fig, ax = plt.subplots(figsize=(13,7))
ax = plt.subplot(121)
cntr = plt.contourf(x,y,func_plot,100,vmin = 0, vmax = 20, alpha = 1)
cbar = fig.colorbar(cntr,orientation="vertical")

Basically I expect to plot a contour image with minimum value = 0 and maximum value = 20. Which gives us the following image:

As you can see from the graph, the ticks at the colorbar starts at 0.00 and ends at 19.8 (the highest tick). However, I want the ticks to end at the top of the bar at the exact maximum value spot of 20 (instead of showing 19.8 as the highest tick value). How can I do that?

I'm sure there's a really simple way to tackle the problem. Thank you for your time.

CodePudding user response：

Colorbars are my bane. This problem is relatively simple yet it took me a few minutes.

Add this line to the end of your code:

cbar.set_ticks(np.arange(0, 21, 5)) # 21 to guarantee 20 is included.

To get this: