Python Forum

The following code is not working and I believe it should.

q = df.loc[df2['machine_status']==0]['time_period']
p = df.loc[df2['machine_status']==1]['time_period'][:q.shape[0]]

pq = np.sum(p * np.log(p/q))
qp = np.sum(q * np.log(q/p))
print('KL(P || Q) : %. pq)%.3f' % pq)
print('KL(Q || P) : %. pq)%.3f' % qp)

It gives me the following error:

Error:KeyError                                  Traceback (most recent call last)
File ~\miniconda3\envs\pump-failure-pred\lib\site-packages\pandas\core\indexes\base.py:3621, in Index.get_loc(self, key, method, tolerance)
   3620 try:
-> 3621     return self._engine.get_loc(casted_key)
   3622 except KeyError as err:

File ~\miniconda3\envs\pump-failure-pred\lib\site-packages\pandas\_libs\index.pyx:136, in pandas._libs.index.IndexEngine.get_loc()

File ~\miniconda3\envs\pump-failure-pred\lib\site-packages\pandas\_libs\index.pyx:163, in pandas._libs.index.IndexEngine.get_loc()

File pandas\_libs\hashtable_class_helper.pxi:5198, in pandas._libs.hashtable.PyObjectHashTable.get_item()

File pandas\_libs\hashtable_class_helper.pxi:5206, in pandas._libs.hashtable.PyObjectHashTable.get_item()

KeyError: 'time_period'

The above exception was the direct cause of the following exception:

KeyError                                  Traceback (most recent call last)
Input In [50], in <cell line: 1>()
----> 1 q = df.loc[df2['machine_status']==0]['time_period']
      2 p = df.loc[df2['machine_status']==1]['time_period'][:q.shape[0]]
      4 pq = np.sum(p * np.log(p/q))

File ~\miniconda3\envs\pump-failure-pred\lib\site-packages\pandas\core\frame.py:3505, in DataFrame.__getitem__(self, key)
   3503 if self.columns.nlevels > 1:
   3504     return self._getitem_multilevel(key)
-> 3505 indexer = self.columns.get_loc(key)
   3506 if is_integer(indexer):
   3507     indexer = [indexer]

File ~\miniconda3\envs\pump-failure-pred\lib\site-packages\pandas\core\indexes\base.py:3623, in Index.get_loc(self, key, method, tolerance)
   3621     return self._engine.get_loc(casted_key)
   3622 except KeyError as err:
-> 3623     raise KeyError(key) from err
   3624 except TypeError:
   3625     # If we have a listlike key, _check_indexing_error will raise
   3626     #  InvalidIndexError. Otherwise we fall through and re-raise
   3627     #  the TypeError.
   3628     self._check_indexing_error(key)

KeyError: 'time_period'

1

Now time period is not an array of numbers and Kullback-Liebler cannot work.

It cannot compare anything but numbers. I am only going to ask for now is that the correct explanation for this error?

I do know what a key error is. Please explain.

I am going to show the last columns so anyone can see that is the error.

I decided to attach a screenshot it is better an easier to show the error.

Respectfully,

LZ

"time_period" is not a column in df. This is easy to test by printing "df" and looking at the columns. "time_period" will not be there. I don't know if this is because there is no time_period column, or if the string doesn't match ("time_period" does not match "time period" or "time_period ").

As far as I can tell, df.loc[df2['machine_status']==0]['time_period'] and df[df2['machine_status']==0]['time_period'] produce the same result.

Led_Zeppelin

deanhystad