如何为轮廓 plot 扩展 matplotlib 颜色条？

Question

The following code produces a contourf plot.

import numpy as np
import matplotlib.pyplot as plt

x = np.linspace(0,10)

X, Y = np.meshgrid(x, x)

F = np.sin(X)*np.cos(Y)

v = np.linspace(-2, 2,10)
plt.contourf(X, Y, F, 500)
cb = plt.colorbar()

F ranges from -1 to 1 so my colorbar has these as its minimum and maximum values. I want the colorbar to range from -2 to 2. I have tried to set the ticks to range from -2 to 2 however this does not work. Any suggestions?

Answer 1

works if you create the colorbar manually:

import numpy as np
import matplotlib as mpl

x = np.linspace(0,10)
X, Y = np.meshgrid(x, x)
F = np.sin(X)*np.cos(Y)

v = np.linspace(-2, 2,10)

f, ax = plt.subplots()
cont = ax.contourf(X, Y, F, 500, vmin=-2, vmax=2, ticks=v)
cax, _ = mpl.colorbar.make_axes(ax)
cbar = mpl.colorbar.ColorbarBase(cax, cmap=cont.cmap, norm=cont.norm)
cbar.set_ticks([v.min(), *np.linspace(F.min(), F.max(), 11), v.max()])