from pandas import *
import matplotlib.pyplot as plt
df=DataFrame([100,200],index=['a','b'],columns=['c'])
df.plot(kind='bar', color='b',width=0.5,rot=0,figsize=(4,4))
index=['a','b']
values=[100,200]
plt.figure(figsize=(4,4))
plt.bar(index,values,color='b',width=0.5)
plt.xlim(-1,2)