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
And if you want to retain any of the aggregation info from the second level of the multiindex you can try this:
In [1]: new_cols = [''.join(t) for t in df.columns]
Out[1]:
['USAF',
'WBAN',
'day',
'month',
's_CDsum',
's_CLsum',
's_CNTsum',
's_PCsum',
'tempfamax',
'tempfamin',
'year']
In [2]: df.columns = new_cols