import pandas as pd
import numpy as np
import matplotlib.pyplot as plt
#导入数据
data=pd.DataFrame(np.random.randint(1,10,(5,3)),columns=["x1","x2","x3"],
                  index=["a","b","c","d","e"])
fig1,ax=plt.subplots(1,1,figsize=(12,6))
ax.plot(data.index,data["x1"],marker="v")
#接下来要在图形中添加值标签，每一个值标签都是一个text对象。
for i in range(len(data.index)):    
    ax.text(i,data["x1"][i],"%2.1f"%(data["x1"][i]),fontsize=12,rotation=0,va="bottom",ha="center")
#"%2.1f"%(data["x1"][i])  是对数值显示格式进行设定，我这里设定数值总位数为2，小数点保留1位，大家可以根据需要自行设定。