Matplotlib：如何为每个子图添加xlabel，title

Question

我尝试使用plt.subplots绘制多个热图。我发现的一个例子如下：

import numpy as np
import matplotlib.pyplot as plt

# Generate some data that where each slice has a different range
# (The overall range is from 0 to 2)
data = np.random.random((4,10,10))
data *= np.array([0.5, 1.0, 1.5, 2.0])[:,None,None]

# Plot each slice as an independent subplot
fig, axes = plt.subplots(nrows=1, ncols=4,figsize=(12,3))
i=0
for dat, ax in zip(data, axes.flat):
    # The vmin and vmax arguments specify the color limits
    im = ax.imshow(dat, vmin=0, vmax=2,cmap='Reds')
    # ax.xlabel(str(i))
    # ax.ylabel(str(i))
    i += 1

# Make an axis for the colorbar on the right side
cax = fig.add_axes([0.95, 0.155, 0.03, 0.67])
fig.colorbar(im, cax=cax)

figtype = 'jpg'
fig.savefig('aaa.jpg',format = figtype,bbox_inches='tight')
fig.tight_layout()

如果我评论以下两行（在上面的例子中完成），代码会成功：

ax.xlabel(str(i))
ax.ylabel(str(i))

如果我使用这两行，我会收到错误说：

AttributeError: 'AxesSubplot' object has no attribute 'xlabel'

如何使其正确？

谢谢大家的帮助!!!