creme target encoding

target_agg.py

>>> from creme import feature_extraction
>>> from creme import stats

>>> X = [
...     {'place': 'Taco Bell', 'revenue': 42},
...     {'place': 'Burger King', 'revenue': 16},
...     {'place': 'Burger King', 'revenue': 24},
...     {'place': 'Taco Bell', 'revenue': 58},
...     {'place': 'Burger King', 'revenue': 20},
...     {'place': 'Taco Bell', 'revenue': 50}
... ]

>>> agg = feature_extraction.TargetAgg(
...     by='place',
...     how=stats.Mean()
... )

>>> for x in X:
...     print(agg.transform_one(x))
...     y = x.pop('revenue')
...     agg = agg.fit_one(x, y)
{'target_mean_by_place': 0.0}
{'target_mean_by_place': 0.0}
{'target_mean_by_place': 16.0}
{'target_mean_by_place': 42.0}
{'target_mean_by_place': 20.0}
{'target_mean_by_place': 50.0}