python中的matshow，其范围在方格的中间打勾

Question

The following code generates a matrix plot that every square of it indexed in the middle with a number from 1 to 39:

import numpy as np
from matplotlib import pyplot as plt
a=np.random.uniform(0,1,1600).reshape((40,40))
fig, ax = plt.subplots(1,1)
ax.matshow(a, vmin = 0, vmax = 1, interpolation = 'none')
label_list=np.arange(0,40,5)
label_list=np.append(label_list,39)
ax.set_xticks(label_list)
ax.set_yticks(label_list)
plt.show()

When I want to change the numbers to be between 0 and 1.95 or basically [0,39]*0.05 the labels shrink to the beginning of axes. If I try to use extent in matshow then the labels don't point to the middle of squares! How can I make this float indices to point to the middle of squares?

Answer 1

import numpy as np
from matplotlib import pyplot as plt

a=np.random.uniform(0,1,1600).reshape((40,40))
fig, ax = plt.subplots(1,1)
ax.matshow(a, vmin = 0, vmax = 1, interpolation = 'none')
tick_list = np.append(np.arange(0,40,5), 39)
label_list=map(lambda x: str(0.05*x), tick_list)
ax.set_xticks(tick_list)
ax.set_xticklabels(label_list)
ax.set_yticks(tick_list)
ax.set_yticklabels(label_list)
plt.show()