Reorder pandas groupby dataframe

Question

I have the following groupby dataframe in pandas

Crop            Region   
maize_1         Temperate    30.0
                Tropical     46.0
maize_2         Tropical     77.5
                Temperate    13.5
soybean_1       Temperate    18.5
                Tropical     35.0

How can I sort it so that in the 'Region' Column, Temperate preceedes Tropical?

-- EDIT: expected answer is

Crop            Region   
maize_1         Temperate    30.0
                Tropical     46.0
maize_2         Temperate    13.5
                Tropical     77.5
soybean_1       Temperate    18.5
                Tropical     35.0

Answer 1

Setup

idx = pd.MultiIndex.from_tuples([('maize_1', 'Temperate'), ('maize_1', 'Tropical'),
                                 ('maize_2', 'Tropical'), ('maize_2', 'Temperate'),
                                 ('soybean_1', 'Temperate'), ('soybean_1', 'Tropical')],
                               names=['Crop', 'Region'])
s = pd.Series([30., 46., 77.5, 13.5, 18.5, 34.], idx)

s

Crop       Region   
maize_1    Temperate    30.0
           Tropical     46.0
maize_2    Tropical     77.5
           Temperate    13.5
soybean_1  Temperate    18.5
           Tropical     34.0
dtype: float64

Solution

IIUC you want to sort by 'Region' and leave 'Crop' alone.

s.unstack().sort_index(1).stack()

Crop       Region   
maize_1    Temperate    30.0
           Tropical     46.0
maize_2    Temperate    13.5
           Tropical     77.5
soybean_1  Temperate    18.5
           Tropical     34.0
dtype: float64

You can also, sort the index as is but it will also sort 'Crop'. It so happens your 'Crop's are already in order. But if they weren't, this solution would preserve that.

Answer 2

Check out sortlevel (docs) or sort_index (docs).

df.sortlevel(level=[0, 1])

and

df.sort_index(level=[0, 1])

both output

Crop       Region   
maize_1    Temperate      30
           Tropical     46.0
maize_2    Temperate    13.5
           Tropical     77.5
soybean_1  Temperate    18.5
           Tropical     35.0