pandas.Series.groupby¶
-
Series.
groupby
(by=None, axis=0, level=None, as_index=True, sort=True, group_keys=True, squeeze=False, observed=False, **kwargs)[source]¶ Group series using mapper (dict or key function, apply given function to group, return result as series) or by a series of columns.
Parameters: by : mapping, function, label, or list of labels
Used to determine the groups for the groupby. If
by
is a function, it’s called on each value of the object’s index. If a dict or Series is passed, the Series or dict VALUES will be used to determine the groups (the Series’ values are first aligned; see.align()
method). If an ndarray is passed, the values are used as-is determine the groups. A label or list of labels may be passed to group by the columns inself
. Notice that a tuple is interpreted a (single) key.- axis : int, default 0
level : int, level name, or sequence of such, default None
If the axis is a MultiIndex (hierarchical), group by a particular level or levels
as_index : boolean, default True
For aggregated output, return object with group labels as the index. Only relevant for DataFrame input. as_index=False is effectively “SQL-style” grouped output
sort : boolean, default True
Sort group keys. Get better performance by turning this off. Note this does not influence the order of observations within each group. groupby preserves the order of rows within each group.
group_keys : boolean, default True
When calling apply, add group keys to index to identify pieces
squeeze : boolean, default False
reduce the dimensionality of the return type if possible, otherwise return a consistent type
observed : boolean, default False
This only applies if any of the groupers are Categoricals If True: only show observed values for categorical groupers. If False: show all values for categorical groupers.
New in version 0.23.0.
Returns: - GroupBy object
See also
resample
- Convenience method for frequency conversion and resampling of time series.
Notes
See the user guide for more.
Examples
DataFrame results
>>> data.groupby(func, axis=0).mean() >>> data.groupby(['col1', 'col2'])['col3'].mean()
DataFrame with hierarchical index
>>> data.groupby(['col1', 'col2']).mean()