Pandas not appending after first column-CodePudding

I have two dataframes. One contains a column that contains the date of earnings for a stock. The other contains the all the prices for the stock, keep in mind that the index is the date. I want to get the prices of a stock N days before and after earnings and store it in a new dataframe column wise. This is what I have so far

earningsPrices = pd.DataFrame()
for date in dates:
    earningsPrices[date] = prices[date - pd.Timedelta(days=N):date   pd.Timedelta(days=N)]
print(earningsPrices)

and this is the output The problem is that it only writes the prices for the first date, and not the rest.

CodePudding user response：

You should maybe take this approach:

earningsPrices = pd.DataFrame(index=dates, columns=['price1', 'price2', 'price3'])

for date in dates:
    start_date = date - pd.Timedelta(days=N)
    end_date = date   pd.Timedelta(days=N)

    selected_rows = prices.loc[prices['date_column'].between(start_date, end_date)]

    earningsPrices.loc[date, 'price1'] = selected_rows['price1'].values
    earningsPrices.loc[date, 'price2'] = selected_rows['price2'].values
    earningsPrices.loc[date, 'price3'] = selected_rows['price3'].values

print(earningsPrices)

CodePudding user response：

use concat

for date in dates:
    earningsPeriod = prices[date - pd.Timedelta(days=window):date   pd.Timedelta(days=window)].reset_index(drop=True)
    earningsPrices = pd.concat([earningsPrices, earningsPeriod], axis=1)