dask_expr._groupby.GroupBy.cumsum

dask_expr._groupby.GroupBy.cumsum

GroupBy.cumsum(numeric_only=False)[source]

Cumulative sum for each group.

This docstring was copied from pandas.core.groupby.groupby.GroupBy.cumsum.

Some inconsistencies with the Dask version may exist.

Returns
Series or DataFrame

See also

Series.groupby

Apply a function groupby to a Series.

DataFrame.groupby

Apply a function groupby to each row or column of a DataFrame.

Examples

For SeriesGroupBy:

>>> lst = ['a', 'a', 'b']  
>>> ser = pd.Series([6, 2, 0], index=lst)  
>>> ser  
a    6
a    2
b    0
dtype: int64
>>> ser.groupby(level=0).cumsum()  
a    6
a    8
b    0
dtype: int64

For DataFrameGroupBy:

>>> data = [[1, 8, 2], [1, 2, 5], [2, 6, 9]]  
>>> df = pd.DataFrame(data, columns=["a", "b", "c"],  
...                   index=["fox", "gorilla", "lion"])
>>> df  
          a   b   c
fox       1   8   2
gorilla   1   2   5
lion      2   6   9
>>> df.groupby("a").groups  
{1: ['fox', 'gorilla'], 2: ['lion']}
>>> df.groupby("a").cumsum()  
          b   c
fox       8   2
gorilla  10   7
lion      6   9