sort_values versus sort giving different answers, but sort_values is the correct answer

Question

I'm wondering what the difference between these two snippets of code could be?

New_Series = pd.Series(df['avg']).sort(axis=0, ascending=False, 
                                       kind='quicksort', na_position='last', 
                                       inplace=True)
New_Series = pd.Series(df['avg']).sort_values(axis=0, ascending=False, 
                                              kind='quicksort', na_position='last', 
                                              inplace=True)

sort_values returns the correct series, but sort returns None.

Is there a difference between these two that makes sort differently from sort_values?

Answer 1

Apart from the fact that sort is deprecated, it returns None when you use inplace=True

sort_values still returns the self updated dataframe is you use that argument as you can see in frame.py source code:

    if inplace:
        return self._update_inplace(new_data)
    else:
        return self._constructor(new_data).__finalize__(self)