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
Answer from EdChum on Stack OverflowUse 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
In pandas 0.21.0+ use parameter level=1:
d = dict(zip(df.columns.levels[1], ["b1", "c1", "f1"]))
print (d)
{'c': 'c1', 'b': 'b1', 'f': 'f1'}
df = df.rename(columns=d, level=1)
print (df)
a d
b1 c1 f1
0 1 2 3
1 10 20 30
2 100 200 300
ENH: Rename multi-level columns or indices using their tupelized names
python - Pandas - Create Multiindex columns during rename - Stack Overflow
python - pandas multiindex columns rename - Stack Overflow
python pandas: rename single column label in multi-index dataframe - Stack Overflow
You could try:
df.columns = pd.MultiIndex.from_tuples(df.rename(columns = nested_columns).columns)
df
Output:
One Two
a c b d
0 27 67 35 36
1 80 42 93 20
2 64 9 18 83
3 85 69 60 84
IIUC, rename
flat_df.rename(columns=nested_columns)
Out[224]:
One Two
a c b d
0 36 19 53 46
1 17 85 63 36
2 40 80 75 86
3 31 83 75 16
Updated
flat_df.columns.map(nested_columns.get)
Out[15]:
MultiIndex(levels=[['One', 'Two'], ['a', 'b', 'c', 'd']],
labels=[[0, 0, 1, 1], [0, 2, 1, 3]])
That is indeed something missing in rename (ideally it should let you specify the level).
Another way is by setting the levels of the columns index, but then you need to know all values for that level:
In [41]: df.columns.levels[0]
Out[41]: Index([u'1', u'2'], dtype='object')
In [43]: df.columns = df.columns.set_levels(['one', 'two'], level=0)
In [44]: df
Out[44]:
one two
A B A B
0 0.899686 0.466577 0.867268 0.064329
1 0.162480 0.455039 0.736870 0.759595
2 0.620960 0.922119 0.060141 0.669997
3 0.871107 0.043799 0.080080 0.577421
In [45]: df.columns.levels[0]
Out[45]: Index([u'one', u'two'], dtype='object')
As of pandas 0.22.0 (and probably much earlier), you can specify the level:
df = df.rename(columns={'1': one, '2': two}, level=0)
or, alternatively (new notation since pandas 0.21.0):
df = df.rename({'1': one, '2': two}, axis='columns', level=0)
But actually, it works even when omitting the level:
df = df.rename(columns={'1': one, '2': two})
In that case, all column levels are checked for occurrences to be renamed.