python 3.x - sorting a dataframe by index -

i have dataframe called df indexed date trying sort oldest date newest.

i have tried use both:

df = df.sort(axis=1) 

and

df = df.sort_index(axis=1) 

but can see date order in following df tail dates have not been sorted date order.

                            wood_density   date                                       2016-01-27                        5.8821   2016-01-28                        5.7760   2015-12-25                           nan   2016-01-01                           nan   2015-12-26                           nan   

could offer assistance please?

many thanks

use sort_index sort index:

in [19]:  df = df.sort_index() df out[19]:             wood_density date                     2015-12-25           nan 2015-12-26           nan 2016-01-01           nan 2016-01-27        5.8821 2016-01-28        5.7760 

sort, deprecated sort_values or sort_index sorts on row labels default axis=0 would've worked if didn't pass this:

in [21]: df.sort()  out[21]:             wood_density date                     2015-12-25           nan 2015-12-26           nan 2016-01-01           nan 2016-01-27        5.8821 2016-01-28        5.7760