# remember in 4.py above, we put the data is in a dataframe, countries.

# 1.
print(countries['CA':'CH']) # same as print(countries['CA':'CH':1])
# 2. above returns
#          Country   Capital  PopulationMillions
#     Code                                      
#     CA    Canada    Ottawa                  37
#     BR    Brazil  Brasilia                 211
#     CH     China   Beijing                1000

# 3.
print(countries[:'CH']) # same as print(countries[:'CH':1])
# 4. above returns
#           Country   Capital  PopulationMillions
#     Code                                       
#     NG    Nigeria     Abuja                 206
#     CA     Canada    Ottawa                  37
#     BR     Brazil  Brasilia                 211
#     CH      China   Beijing                1000

# 5.
print(countries['CA':]) # same as print(countries['CA'::1])
# 6. above returns
#         Country   Capital  PopulationMillions
#     Code                                      
#     CA    Canada    Ottawa                  37
#     BR    Brazil  Brasilia                 211
#     CH     China   Beijing                1000
#     FR    France     Paris                  11

# 7.
print(countries['NG'::2])
# 8. above returns
#           Country   Capital  PopulationMillions
#     Code                                       
#     NG    Nigeria     Abuja                 206
#     BR     Brazil  Brasilia                 211
#     FR     France     Paris                  11

# 9.
print(countries[:'CA':-1])
# 10. above returns
#         Country   Capital  PopulationMillions
#     Code                                      
#     FR    France     Paris                  11
#     CH     China   Beijing                1000
#     BR    Brazil  Brasilia                 211
#     CA    Canada    Ottawa                  37