In [ ]:

    

import pandas as pd
stock = pd.read_csv('N225_data.txt', sep='\s+', index_col=0)
stock.index = stock.index.astype('datetime64[ns]')
stock.tail()
stock.resample('MS').mean().to_csv('N225_data_monthly.txt', sep='\t')


    

In [ ]:

    

import pandas as pd
stock = pd.read_csv('FTSE100_data.txt', sep='\s+', index_col=0)
stock.index = stock.index.astype('datetime64[ns]')
stock.tail()
stock.resample('MS').mean().to_csv('FTSE100_data_monthly.txt', sep='\t')