import pandas as pd
import numpy as np

dates = pd.date_range('20130101', periods=6)
df = pd.DataFrame(np.arange(24).reshape((6, 4)), index=dates, columns=['A', 'B', 'C', 'D'])

df.iloc[2, 2] = 1111
df.loc['20130101', 'B'] = 2222
df.B[df.A > 4] = 0
df['F']=np.nan
df['E']=pd.Series([1,2,3,4,5,6],index=pd.date_range('20130101',periods=6))
print(df)
