Colorbar scientific notation, change e^ to 10^

Question

I am using scientific notation in a colorbar within a 2D plot. I want to write 10^{-3} instead of e-3. I tried to change that (see code below) but it does not work...

import numpy as np
import matplotlib.pyplot as plt
import matplotlib.ticker

x = np.random.rand(100)
y = np.random.rand(100)
z = np.random.rand(100)*0.001

x=x.reshape((10,10))

y=y.reshape((10,10))

z=z.reshape((10,10))

fig, ax = plt.subplots(figsize=(8,6))

cs = ax.contourf(x,y,z, 10)

plt.xticks(fontsize=16,rotation=0)
plt.yticks(fontsize=16,rotation=0)

cbar = plt.colorbar(cs,)
cbar.set_label("test",fontsize = 22)


cbar.formatter.set_scientific(True)
cbar.formatter.set_powerlimits((0, 0))
cbar.ax.tick_params(labelsize=16)
cbar.ax.yaxis.get_offset_text().set_fontsize(22)

cbar.ax.xaxis.major.formatter._useMathText = True

cbar.update_ticks()  

plt.savefig("test.png")

Answer 1

@ImportanceOfBeingErnesto's answer is nice, but you don't have to use your own formatter since ScalarFormatter is used by default anyways. This approach is simpler and gives the same result:

import numpy as np
import matplotlib.pyplot as plt

x = np.tile(np.arange(10), 10).reshape((10,10))
y = np.repeat(np.arange(10),10).reshape((10,10))
z = np.sort(np.random.rand(100)*1e-3).reshape((10,10))

fig, ax = plt.subplots(figsize=(8,6))
cs = ax.contourf(x,y,z, 10)

cbar = plt.colorbar(cs)
cbar.formatter.set_powerlimits((0, 0))
cbar.formatter.set_useMathText(True)

plt.show()

Answer 2

It seems you want a ScalarFormatter with mathtext in use.

import numpy as np
import matplotlib.pyplot as plt
import matplotlib.ticker

x = np.tile(np.arange(10), 10).reshape((10,10))
y = np.repeat(np.arange(10),10).reshape((10,10))
z = np.sort(np.random.rand(100)*0.001).reshape((10,10))

fig, ax = plt.subplots(figsize=(8,6))
cs = ax.contourf(x,y,z, 10)

fmt = matplotlib.ticker.ScalarFormatter(useMathText=True)
fmt.set_powerlimits((0, 0))
cbar = plt.colorbar(cs,format=fmt)

plt.show()