Pandas - How to flatten a hierarchical index in columns

Question

I have a data frame with a hierarchical index in axis 1 (columns) (from a groupby.agg operation):

     USAF   WBAN  year  month  day  s_PC  s_CL         


        

Answer 1

I'll share a straight-forward way that worked for me.

[" ".join([str(elem) for elem in tup]) for tup in df.columns.tolist()]
#df = df.reset_index() if needed