gistfile1.py

import matplotlib.pyplot as plt
import numpy as np

x = np.random.rand(10)
_, _, patches = plt.hist(x, bins=3)
labels = ["label%d" % i for i in range(len(patches))]
for rect, label in zip(patches, labels):
  height = rect.get_height()
  plt.gca().text(rect.get_x() + rect.get_width() / 2, height, label,
                 ha='center', va='bottom')
plt.show()