python直方图如何显示值?

plt.text(x, y, string, weight="bold", color="b")

# -*- coding: utf-8 -*-

import matplotlib.pyplot as plt

#num_list = [1.5,0.6,7.8,6]

fig, ax = plt.subplots()

num_list = [7870,81937,17529598,6225227]

name_list = ['Eviction','Failed','Finished','Killed']

b = ax.bar(name_list, num_list)

plt.bar(range(len(num_list)), num_list,color='rbg',tick_label=name_list)

for a, b in zip(name_list, num_list):

    ax.text(a, b+1, b, ha='center', va='bottom')

plt.title('Numbers of Four eventtypes')

plt.xlabel('Eventtype')

plt.ylabel('Number')

plt.show()