pandas.core.groupby.GroupBy.first#

final GroupBy.first(numeric_only=False, min_count=- 1)[source]#

Compute the first non-null entry of each column.

Parameters

numeric_onlybool, default False: Include only float, int, boolean columns.
min_countint, default -1: The required number of valid values to perform the operation. If fewer than min_count non-NA values are present the result will be NA.

Returns

Series or DataFrame: First non-null of values within each group.

See also

DataFrame.groupby: Apply a function groupby to each row or column of a DataFrame.
DataFrame.core.groupby.GroupBy.last: Compute the last non-null entry of each column.
DataFrame.core.groupby.GroupBy.nth: Take the nth row from each group.

Examples

>>> df = pd.DataFrame(dict(A=[1, 1, 3], B=[None, 5, 6], C=[1, 2, 3],
...                        D=['3/11/2000', '3/12/2000', '3/13/2000']))
>>> df['D'] = pd.to_datetime(df['D'])
>>> df.groupby("A").first()
     B  C          D
A
1  5.0  1 2000-03-11
3  6.0  3 2000-03-13
>>> df.groupby("A").first(min_count=2)
    B    C          D
A
1 NaN  1.0 2000-03-11
3 NaN  NaN        NaT
>>> df.groupby("A").first(numeric_only=True)
     B  C
A
1  5.0  1
3  6.0  3