pandas.core.groupby.DataFrameGroupBy.value_counts#

DataFrameGroupBy.value_counts(subset=None, normalize=False, sort=True, ascending=False, dropna=True)[source] #

Return a Series or DataFrame containing counts of unique rows.

Added in version 1.4.0.

Parameters:
subsetlist-like, optional

Columns to use when counting unique combinations.

normalizebool, default False

Return proportions rather than frequencies.

sortbool, default True

Sort by frequencies.

ascendingbool, default False

Sort in ascending order.

dropnabool, default True

Don’t include counts of rows that contain NA values.

Returns:
Series or DataFrame

Series if the groupby as_index is True, otherwise DataFrame.

See also

Series.value_counts

Equivalent method on Series.

DataFrame.value_counts

Equivalent method on DataFrame.

SeriesGroupBy.value_counts

Equivalent method on SeriesGroupBy.

Notes

  • If the groupby as_index is True then the returned Series will have a MultiIndex with one level per input column.

  • If the groupby as_index is False then the returned DataFrame will have an additional column with the value_counts. The column is labelled ‘count’ or ‘proportion’, depending on the normalize parameter.

By default, rows that contain any NA values are omitted from the result.

By default, the result will be in descending order so that the first element of each group is the most frequently-occurring row.

Examples

>>> df = pd.DataFrame({
...  'gender': ['male', 'male', 'female', 'male', 'female', 'male'],
...  'education': ['low', 'medium', 'high', 'low', 'high', 'low'],
...  'country': ['US', 'FR', 'US', 'FR', 'FR', 'FR']
... })

>>> df
 gender education country
0 male low US
1 male medium FR
2 female high US
3 male low FR
4 female high FR
5 male low FR

>>> df.groupby('gender').value_counts()
gender education country
female high FR 1
 US 1
male low FR 2
 US 1
 medium FR 1
Name: count, dtype: int64

>>> df.groupby('gender').value_counts(ascending=True)
gender education country
female high FR 1
 US 1
male low US 1
 medium FR 1
 low FR 2
Name: count, dtype: int64

>>> df.groupby('gender').value_counts(normalize=True)
gender education country
female high FR 0.50
 US 0.50
male low FR 0.50
 US 0.25
 medium FR 0.25
Name: proportion, dtype: float64

>>> df.groupby('gender', as_index=False).value_counts()
 gender education country count
0 female high FR 1
1 female high US 1
2 male low FR 2
3 male low US 1
4 male medium FR 1

>>> df.groupby('gender', as_index=False).value_counts(normalize=True)
 gender education country proportion
0 female high FR 0.50
1 female high US 0.50
2 male low FR 0.50
3 male low US 0.25
4 male medium FR 0.25