pandas.Series.xs#

Series.xs(key, axis=0, level=None, drop_level=True)[source] #

Return cross-section from the Series/DataFrame.

This method takes a key argument to select data at a particular level of a MultiIndex.

Parameters:

keylabel or tuple of label: Label contained in the index, or partially in a MultiIndex.
axis{0 or ‘index’, 1 or ‘columns’}, default 0: Axis to retrieve cross-section on.
levelobject, defaults to first n levels (n=1 or len(key)): In case of a key partially contained in a MultiIndex, indicate which levels are used. Levels can be referred by label or position.
drop_levelbool, default True: If False, returns object with same levels as self.

Returns:

Series or DataFrame: Cross-section from the original Series or DataFrame corresponding to the selected index levels.

See also

DataFrame.loc: Access a group of rows and columns by label(s) or a boolean array.
DataFrame.iloc: Purely integer-location based indexing for selection by position.

Notes

xs can not be used to set values.

MultiIndex Slicers is a generic way to get/set values on any level or levels. It is a superset of xs functionality, see MultiIndex Slicers.

Examples

>>> d = {'num_legs': [4, 4, 2, 2],
...  'num_wings': [0, 0, 2, 2],
...  'class': ['mammal', 'mammal', 'mammal', 'bird'],
...  'animal': ['cat', 'dog', 'bat', 'penguin'],
...  'locomotion': ['walks', 'walks', 'flies', 'walks']}
>>> df = pd.DataFrame(data=d)
>>> df = df.set_index(['class', 'animal', 'locomotion'])
>>> df
 num_legs num_wings
class animal locomotion
mammal cat walks 4 0
 dog walks 4 0
 bat flies 2 2
bird penguin walks 2 2

Get values at specified index

>>> df.xs('mammal')
 num_legs num_wings
animal locomotion
cat walks 4 0
dog walks 4 0
bat flies 2 2

Get values at several indexes

>>> df.xs(('mammal', 'dog', 'walks'))
num_legs 4
num_wings 0
Name: (mammal, dog, walks), dtype: int64

Get values at specified index and level

>>> df.xs('cat', level=1)
 num_legs num_wings
class locomotion
mammal walks 4 0

Get values at several indexes and levels

>>> df.xs(('bird', 'walks'),
...  level=[0, 'locomotion'])
 num_legs num_wings
animal
penguin 2 2

Get values at specified column and axis

>>> df.xs('num_wings', axis=1)
class animal locomotion
mammal cat walks 0
 dog walks 0
 bat flies 2
bird penguin walks 2
Name: num_wings, dtype: int64