ngroup(self, ascending: 'bool' = True)

This is the enumerative complement of cumcount. Note that the numbers given to the groups match the order in which the groups would be seen when iterating over the groupby object, not the order they are first observed.

Parameters

ascending : bool, default True

If False, number in reverse, from number of group - 1 to 0.

Returns

Series

Unique numbers for each group.

Number each group from 0 to the number of groups - 1.

See Also

.cumcount

Number the rows in each group.

Examples

This example is valid syntax, but we were not able to check execution

>>> df = pd.DataFrame({"A": list("aaabba")})
... df
   A
0  a
1  a
2  a
3  b
4  b
5  a

This example is valid syntax, but we were not able to check execution

>>> df.groupby('A').ngroup()
0    0
1    0
2    0
3    1
4    1
5    0
dtype: int64

This example is valid syntax, but we were not able to check execution

>>> df.groupby('A').ngroup(ascending=False)
0    1
1    1
2    1
3    0
4    0
5    1
dtype: int64

This example is valid syntax, but we were not able to check execution

>>> df.groupby(["A", [1,1,2,3,2,1]]).ngroup()
0    0
1    0
2    1
3    3
4    2
5    0
dtype: int64

See :

Back References

The following pages refer to to this document either explicitly or contain code examples using this.

pandas.core.groupby.groupby.GroupBy.cumcount

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File: /pandas/core/groupby/groupby.py#2970
type: <class 'function'>
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