pandas.Grouper¶

class pandas.Grouper(key=None, level=None, freq=None, axis=0, sort=False)[source]¶

A Grouper allows the user to specify a groupby instruction for an object.

This specification will select a column via the key parameter, or if the level and/or axis parameters are given, a level of the index of the target object.

If axis and/or level are passed as keywords to both Grouper and groupby, the values passed to Grouper take precedence.

Parameters

keystr, defaults to None: Groupby key, which selects the grouping column of the target.
levelname/number, defaults to None: The level for the target index.
freqstr / frequency object, defaults to None: This will groupby the specified frequency if the target selection (via key or level) is a datetime-like object. For full specification of available frequencies, please see here.
axisstr, int, defaults to 0: Number/name of the axis.
sortbool, default to False: Whether to sort the resulting labels.
closed{‘left’ or ‘right’}: Closed end of interval. Only when freq parameter is passed.
label{‘left’ or ‘right’}: Interval boundary to use for labeling. Only when freq parameter is passed.
convention{‘start’, ‘end’, ‘e’, ‘s’}: If grouper is PeriodIndex and freq parameter is passed.
baseint, default 0: Only when freq parameter is passed.
loffsetstr, DateOffset, timedelta object: Only when freq parameter is passed.

Returns

A specification for a groupby instruction

Examples

Syntactic sugar for df.groupby('A')

>>> df.groupby(Grouper(key='A'))

Specify a resample operation on the column ‘date’

>>> df.groupby(Grouper(key='date', freq='60s'))

Specify a resample operation on the level ‘date’ on the columns axis with a frequency of 60s

>>> df.groupby(Grouper(level='date', freq='60s', axis=1))

Attributes

ax
groups