as I have mentioned in title, I fail to make it happened in my code. Here is my code, I try to use the two methods, but eventually it still cannot work.
# using python 2.7.12
import pandas as pd
dates = pd.date_range('20141001', periods = 7)
import numpy as np
dates1 = pd.DataFrame(np.random.randn(7,3), index =dates, columns = list('ABC'))
print dates1
dates2 = pd.DataFrame(np.random.randint(0,100), index =dates, columns = list('ABC'))