pandas.core.groupby.SeriesGroupBy.cummax — pandas 2.2.3 documentation (original) (raw)

SeriesGroupBy.cummax(axis=<no_default>, numeric_only=False, **kwargs)[source]#

Cumulative max for each group.

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', 'a', 'b', 'b', 'b'] ser = pd.Series([1, 6, 2, 3, 1, 4], index=lst) ser a 1 a 6 a 2 b 3 b 1 b 4 dtype: int64 ser.groupby(level=0).cummax() a 1 a 6 a 6 b 3 b 3 b 4 dtype: int64

For DataFrameGroupBy:

data = [[1, 8, 2], [1, 1, 0], [2, 6, 9]] df = pd.DataFrame(data, columns=["a", "b", "c"], ... index=["cow", "horse", "bull"]) df a b c cow 1 8 2 horse 1 1 0 bull 2 6 9 df.groupby("a").groups {1: ['cow', 'horse'], 2: ['bull']} df.groupby("a").cummax() b c cow 8 2 horse 8 2 bull 6 9