Calculate slippage for buy and sell orders

Installations & Python Packages
1

What am i doing wrong in the code below: 



I have tried to wrap everything in parenthensis but still gets an error. any help would be appreciated. 





#Calculate slippage for buy orders



aapl_1m['slippage_buy_order'] = (aapl_1m['High']  - aapl_1m['Close']) / aapl_1m['Close']



#Calculate slippage for sell orders



aapl_1m['slippage_sell_order'] = (aapl_1m['Close'] - aapl_1m['Low']) / aapl_1m['Close']



#Mean of the slippage for buy and sell orders for each day



aapl_1m = aapl_1m.groupby([aapl_1m['Date'].dt.date]).mean



aapl_1m







I am getting this error message: 

 

TypeError                                 Traceback (most recent call last)
<ipython-input-32-1931dbd8d2a6> in <module>
      1 #Calculate slippage for buy orders
      2 
----> 3 aapl_1m['slippage_buy_order'] = (aapl_1m['High']  - aapl_1m['Close']) / aapl_1m['Close']
      4 
      5 #Calculate slippage for sell orders

TypeError: 'method' object is not subscriptable

 
2

You need to call the mean() function like the below code. 



aapl_1m = aapl_1m.groupby([aapl_1m['Date'].dt.date]).mean()