Use set_levels
:
In [22]:
df.columns.set_levels(['b1','c1','f1'],level=1,inplace=True)
df
Out[22]:
a d
b1 c1 f1
0 1 2 3
1 10 20 30
2 100 200 300
rename
sets the name for the index, it doesn’t rename the column names:
In [26]:
df.columns = df.columns.rename("b1", level=1)
df
Out[26]:
a d
b1 b c f
0 1 2 3
1 10 20 30
2 100 200 300
This is why you get the error