[FIXED] Money Flow Index keyerror

Issue

I've obtained the historical values from an example stock (Apple in this case) and was following an example I saw online, however, when their code succeeded mine failed because of some keyerror? Could anyone tell/show me what's wrong and hopefully how to fix it? Error is:

KeyError                                  Traceback (most recent call last)
~\anaconda3\lib\site-packages\pandas\core\indexes\base.py in get_loc(self, key, method, tolerance)
   2645             try:
-> 2646                 return self._engine.get_loc(key)
   2647             except KeyError:

pandas\_libs\index.pyx in pandas._libs.index.IndexEngine.get_loc()

pandas\_libs\index.pyx in pandas._libs.index.IndexEngine.get_loc()

pandas\_libs\hashtable_class_helper.pxi in pandas._libs.hashtable.PyObjectHashTable.get_item()

pandas\_libs\hashtable_class_helper.pxi in pandas._libs.hashtable.PyObjectHashTable.get_item()

KeyError: 1

During handling of the above exception, another exception occurred:

KeyError                                  Traceback (most recent call last)
<ipython-input-60-d89407b24e87> in <module>
      3 
      4 for i in range(1, len(typical_price)):
----> 5     if typical_price[i] > typical_price[i-1]:
      6         positive_flow.append(money_flow[i-1])
      7         negative_flow.append(0)

~\anaconda3\lib\site-packages\pandas\core\frame.py in __getitem__(self, key)
   2798             if self.columns.nlevels > 1:
   2799                 return self._getitem_multilevel(key)
-> 2800             indexer = self.columns.get_loc(key)
   2801             if is_integer(indexer):
   2802                 indexer = [indexer]

~\anaconda3\lib\site-packages\pandas\core\indexes\base.py in get_loc(self, key, method, tolerance)
   2646                 return self._engine.get_loc(key)
   2647             except KeyError:
-> 2648                 return self._engine.get_loc(self._maybe_cast_indexer(key))
   2649         indexer = self.get_indexer([key], method=method, tolerance=tolerance)
   2650         if indexer.ndim > 1 or indexer.size > 1:

pandas\_libs\index.pyx in pandas._libs.index.IndexEngine.get_loc()

pandas\_libs\index.pyx in pandas._libs.index.IndexEngine.get_loc()

pandas\_libs\hashtable_class_helper.pxi in pandas._libs.hashtable.PyObjectHashTable.get_item()

pandas\_libs\hashtable_class_helper.pxi in pandas._libs.hashtable.PyObjectHashTable.get_item()

KeyError: 1

---

Code is:

import matplotlib.pyplot as plt
import pandas as pd
import numpy as np
import math
import pandas_datareader as pdr

stocks = ['AAPL']
data_close = pdr.get_data_yahoo(stocks, start='2020-01-01')['Close']
data_high = pdr.get_data_yahoo(stocks, start='2020-01-01')['High']
data_low = pdr.get_data_yahoo(stocks, start='2020-01-01')['Low']
data_volume = pdr.get_data_yahoo(stocks, start='2020-01-01')['Volume']
typical_price = (data_close + data_high + data_low)/3;
money_flow = typical_price * data_volume;
    
positive_flow = []
negative_flow = []

for i in range(1, len(typical_price)):
    if typical_price[i] > typical_price[i-1]:
        positive_flow.append(money_flow[i-1])
        negative_flow.append(0)
    elif typical_price[i] < typical_price[i-1]:
        positive_flow.append(0)
        negative_flow.append(money_flow[i-1])
    else:
        positive_flow.append(0)
        negative_flow.append(0)

Error appears when I run the final part of the code where I try to retrieve the positive and negative moneyflow for my MFI algorithm.

Solution

Use iloc indexing

for i in range(1, len(typical_price)):
    if typical_price.iloc[i].item() > typical_price.iloc[i-1].item():
        positive_flow.append(money_flow.iloc[i-1])
        negative_flow.append(0)
    elif typical_price.iloc[i].item() < typical_price.iloc[i-1].item():
        positive_flow.append(0)
        negative_flow.append(money_flow.iloc[i-1])
    else:
        positive_flow.append(0)
        negative_flow.append(0)

typical_price and money_flow probably has datetime as index not integers. If you want access row by integer-location then you can use iloc

Answered By - Dishin H Goyani