Using .loc on just second index in multiindex
If you prefer loc
, you can use:
In [245]: df.loc[(slice(None), 'Ai'), :]
...:
Out[245]:
value
year name
1921 Ai 90
1922 Ai 7
I would use .xs
on the first level of your multiindex (note: level=1
refers to the "second" index (name
) because of python's zero indexing: level 0 is year
in your case):
df.xs('Ai', level=1, drop_level=False)
# or
df.xs('Ai', level='name', drop_level=False)
value
year name
1921 Ai 90
1922 Ai 7
@sacul has the most idiomatic answer, but here are a few alternatives.
MultiIndex.get_level_values
df[df.index.get_level_values('name') == 'Ai']
value
year name
1921 Ai 90
1922 Ai 7
DataFrame.query
df.query('name == "Ai"')
value
year name
1921 Ai 90
1922 Ai 7
DataFrame.loc(axis=0)
with pd.IndexSlice
Similar to @liliscent's answer, but does not need the trailing :
if you specify axis=0
.
df.loc(axis=0)[pd.IndexSlice[:, 'Ai']]
value
year name
1921 Ai 90
1922 Ai 7