General list size question to solve problem

[bowlofred]

xx[horse_count] is not a list but a numpy array. It's telling you the numpy array has size 98. That means since the array is zero-indexed, the largest index you can request is 97. Asking for xx[horse_count][98] is too big.

>>> arr = np.ones(98)
>>> arr[97]
1.0
>>> arr[98]
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
IndexError: index 98 is out of bounds for axis 0 with size 98