In [1]: import pandas as pd
In [2]: s = pd.Series([3,4,0,3]).sort()
In [3]: s
Indeed In [3] will output nothing, as you can check:
In [4]: type(s)
Out[4]: NoneType
The reason:
pd.Series([3,4,0,3]) indeed return a pandas Series type object, BUT Series.sort() method return nothing because of inplace sorting. So the expression s = pd.Series([3,4,0,3]).sort(), s in LHS get nothing from RHS, thus In [3]: s output nothing.
NOTE that:
After version 0.17.0, sorting by value methods pandas.Series.sort() and pandas.Series.order() are DEPRECATED, replaced by a unified pandas.Series.sort_values() API. See this answer for more details.
