PRP PRP - 2 days ago 5
Python Question

How to change the least count of axis in mathplotlib

I have the following script to generate a heatmap of NxN cores :

import matplotlib.pyplot as plt
import matplotlib.patches as mpatches
import numpy as np

matrix = np.random.randint(300,high=400, size=(4, 4))

heatmap = plt.pcolor(np.array(matrix))

for y in range(len(matrix)):
for x in range(len(matrix[0])):
plt.text(x + 0.5, y + 0.5, '%.4f' % matrix[y][x],
horizontalalignment='center',
verticalalignment='center',
)

plt.colorbar(heatmap)
plt.xlabel ("Cores")
plt.ylabel ("Cores")
plt.title ("Temperature Map of the NxN Cores")
plt.savefig ("xyz"+".png")
plt.show()
plt.clf()


It produces this :

As each of squares depict a core, the values of
0.5
,
1.5
etc. don't make any sense.

I want the axis values to be integers only. I looked up the docs for this but could not find a way to achieve this.

Answer

You can explicitly set where you want to tick marks with plt.xticks and plt.yticks.

For your example:

plt.xticks(range(min(x), max(x)+1))
plt.yticks(range(min(y), max(y)+1))
plt.show()

If your data in not integers, you could use:

import numpy as np
plt.xticks(np.arange(min(x), max(x)+1, 1.0))
plt.yticks(np.arange(min(y), max(y)+1, 1.0))
plt.show()
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