dask.dataframe.tseries.resample.Resampler.first

dask.dataframe.tseries.resample.Resampler.first

Resampler.first()[source]

Compute the first non-null entry of each column.

This docstring was copied from pandas.core.resample.Resampler.first.

Some inconsistencies with the Dask version may exist.

Parameters
numeric_onlybool, default False (Not supported in Dask)

Include only float, int, boolean columns.

min_countint, default -1 (Not supported in Dask)

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