Python heatmap plot colorbar

Question

I am working on a plot which looks like this so far:

And I am using the following code:

import matplotlib.pyplot as plt
import numpy as np
column_labels = ['A','B']
row_labels = ['A','B']
data = np.random.rand(2,2)
print(type(data))
data = np.array([[1, 0.232], [0.119, 1]])
fig, ax = plt.subplots()
heatmap = ax.pcolor(data, cmap=plt.cm.Blues)

# put the major ticks at the middle of each cell
ax.set_xticks(np.arange(data.shape[0])+0.5, minor=False)
ax.set_yticks(np.arange(data.shape[1])+0.5, minor=False)

# want a more natural, table-like display
ax.invert_yaxis()
ax.xaxis.tick_top()

ax.set_xticklabels(row_labels, minor=False)
ax.set_yticklabels(column_labels, minor=False)
plt.show()

What I am trying to get is something like this one:

Where I can see the color bar as well as value of the cells on them. What would I need to add to my code to get these?

Thanks

Answer 1

Have you looked into seaborn?

import seaborn as sns
data = np.random.rand(2,2)
sns.heatmap(data, annot=True,  linewidths=.5)

Answer 2

For the color bar, see this example . You guessed correctly, the right function call is just ax.colorbar() .

Concerning the values on the pcolor plot, I'm afraid you have to add them "manually" using ax.text() . Calculate and loop over the cell center values and call the text() function. You can use the keyword arguments horizontalalignment='center' and verticalalignment='center' to keep the text value centered around x, y .