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

Essentially this is equivalent to

.. code-block:: python
    self.apply(lambda x: pd.Series(np.arange(len(x)), x.index))

Parameters

ascending : bool, default True

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

Returns

Series

Sequence number of each element within each group.

Number each item in each group from 0 to the length of that group - 1.

See Also

.ngroup

Number the groups themselves.

Examples

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

>>> df = pd.DataFrame([['a'], ['a'], ['a'], ['b'], ['b'], ['a']],
...                   columns=['A'])
... 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').cumcount()
0    0
1    1
2    2
3    0
4    1
5    3
dtype: int64

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

>>> df.groupby('A').cumcount(ascending=False)
0    3
1    2
2    1
3    1
4    0
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.ngroup

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File: /pandas/core/groupby/groupby.py#3040
type: <class 'function'>
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