45. Matplotlib: A simple heatmap

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Heatmaps may be generated with imshow.

We import a colour map from the library cm.

For a list of colour maps available see: https://matplotlib.org/examples/color/colormaps_reference.html

import numpy as np
import matplotlib.pyplot as plt
from matplotlib import cm # This allows different color schemes

# Generate an array of increasing values
a=np.arange(0,400)
a = a.reshape(20,20)

# Plot the heatmap using 'inferno' from the cm colour schemes

plt.imshow(a,interpolation='nearest', cmap=cm.inferno)

# Add a scale bar

plt.colorbar()

plt.show()