Scientific notation colorbar in matplotlib

I am trying to put a colorbar to my image using matplotlib. The issue comes when I try to force the ticklabels to be written in scientific notation. How can I force the scientific notation (ie, 1×10^0, 2×10^0, …, 1×10^2, and so on) in the ticks of the color bar?

Example, let’s create and plot and image with its color bar:

import matplotlib as plot
import numpy as np

img = np.random.randn(300,300)
myplot = plt.imshow(img)
plt.colorbar(myplot)
plt.show()

When I do this, I get the following image:

However, I would like to see the ticklabels in scientific notation… Is there any one line command to do this? Otherwise, is there any hint out there? Thanks!

Answer

You could use colorbar‘s format parameter:

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

img = np.random.randn(300,300)
myplot = plt.imshow(img)

def fmt(x, pos):
    a, b = '{:.2e}'.format(x).split('e')
    b = int(b)
    return r'${} times 10^{{{}}}$'.format(a, b)

plt.colorbar(myplot, format=ticker.FuncFormatter(fmt))
plt.show()