Can anyone explain me whats happening here?

[Puxk]

I'm not sure if this goes in homework or datascience but it is related to pandas so here goes

df[df['TotalPayBenefits'].max()]

why does this result in a error while

df[df['TotalPayBenefits']==df['TotalPayBenefits'].max()]

works fine

Error:
---------------------------------------------------------------------------
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: 567595.43

During handling of the above exception, another exception occurred:

KeyError                                  Traceback (most recent call last)
<ipython-input-24-d77051c168c8> in <module>
----> 1 df[df['TotalPayBenefits'].max()]

~\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: 567595.43

the KeyError is kind of my answer while it doesnt fetch me the name of the person whose salary it corresponds with

[jefsummers]

In the first snippet, you are selecting a dataframe with a single value - the max of that column. Pandas does not know if you want the rows with that value in the same column, a different column, or whatever. In the second snippet you select where two values are equal - the value in the oclumn TotalBenefits and the value of the max(). It's kind of like saying "if the value in TotalBenefits equals the max of TotalBenefits, include that row in the selection.

And of course, remember you are doing selections, not creating a new dataframe. To do that you need to use copy. That's a common gotcha.