def _analyze(self, data):
"""Build a ``dict`` with column names and transformers from a given ``pandas.DataFrame``.
When ``self.dtypes`` is ``None``, use the dtypes from the input data.
When ``dtype`` is:
- ``int``: a ``NumericalTransformer`` is created with ``dtype=int``.
- ``float``: a ``NumericalTransformer`` is created with ``dtype=float``.
- ``object`` or ``category``: a ``CategoricalTransformer`` is created.
- ``bool``: a ``BooleanTransformer`` is created.
- ``datetime``: a ``DatetimeTransformer`` is created.
Any other ``dtype`` is not supported and raises a ``ValueError``.
Args:
data (pandas.DataFrame):
Data used to analyze the ``pandas.DataFrame`` dtypes.
Returns:
dict:
Mapping of column names and transformer instances.
Raises:
ValueError:
if a ``dtype`` is not supported by the `HyperTransformer``.
"""
transformers = dict()
dtypes = self.dtypes or data.dtypes
if self.dtypes:
dtypes = self.dtypes
else:
dtypes = [
data[column].dropna().infer_objects()
for column in data.columns
]
for name, dtype in zip(data.columns, dtypes):
dtype = np.dtype(dtype)
if dtype.kind == 'i':
transformer = NumericalTransformer(dtype=int)
elif dtype.kind == 'f':
transformer = NumericalTransformer(dtype=float)
elif dtype.kind == 'O':
anonymize = self.anonymize.get(name)
transformer = CategoricalTransformer(anonymize=anonymize)
elif dtype.kind == 'b':
transformer = BooleanTransformer()
elif dtype.kind == 'M':
transformer = DatetimeTransformer()
else:
raise ValueError('Unsupported dtype: {}'.format(dtype))
transformers[name] = transformer
return transformers
def test_transform_series(self):
"""Test transform pandas.Series"""
# Setup
data = pd.Series([1.5, None, 2.5])
# Run
transformer = Mock()
NumericalTransformer.transform(transformer, data)
# Asserts
expect_call_count = 1
self.assertEqual(transformer.null_transformer.transform.call_count,
expect_call_count,
"Transform must be called only once")
def test_transform_array(self):
"""Test transform numpy.array"""
# Setup
data = np.array([1.5, None, 2.5])
# Run
transformer = Mock()
NumericalTransformer.transform(transformer, data)
# Asserts
expect_call_count = 1
self.assertEqual(transformer.null_transformer.transform.call_count,
expect_call_count,
"Transform must be called only once")
def test_fit_nan_ignore_array(self):
"""Test fit nan ignore with numpy.array"""
# Setup
data = np.array([1.5, None, 2.5])
# Run
transformer = NumericalTransformer(dtype=np.float, nan=None)
transformer.fit(data)
# Asserts
expect_fill_value = None
expect_dtype = np.float
self.assertEqual(transformer.null_transformer.fill_value,
expect_fill_value, "Data mean is wrong")
self.assertEqual(transformer._dtype, expect_dtype,
"Expected dtype: float")
def test_fit_nan_mode_series(self):
"""Test fit nan mode with pandas.Series"""
# Setup
data = pd.Series([1.5, None, 2.5])
# Run
transformer = NumericalTransformer(dtype=np.float, nan='mode')
transformer.fit(data)
# Asserts
expect_fill_value = 1.5
expect_dtype = np.float
self.assertEqual(transformer.null_transformer.fill_value,
expect_fill_value, "Data mean is wrong")
self.assertEqual(transformer._dtype, expect_dtype,
"Expected dtype: float")
def test___init__(self):
"""Test default instance"""
# Run
transformer = NumericalTransformer()
# Asserts
self.assertEqual(transformer.nan, 'mean', "Unexpected nan")
self.assertIsNone(transformer.null_column,
"null_column is None by default")
self.assertIsNone(transformer.dtype, "dtype is None by default")
def test_reverse_transform_nan_not_ignore(self):
"""Test reverse_transform with nan not equal to ignore"""
# Setup
data = pd.Series([1.5, 2.0, 2.5])
reversed_data = pd.Series([1.5, 2.0, 2.5])
# Run
transformer = Mock()
transformer.nan = 'mean'
transformer._dtype = np.float
transformer.null_transformer.nulls = False
transformer.null_transformer.reverse_transform.return_value = reversed_data
NumericalTransformer.reverse_transform(transformer, data)
# Asserts
expected_reverse_transform_call_count = 1
self.assertEqual(
transformer.null_transformer.reverse_transform.call_count,
expected_reverse_transform_call_count,
"NullTransformer.reverse_transform must be called at least once")
def test_reverse_transform_dtype_int(self, numpy_mock):
"""Test reverse_transform with dtype equal to int"""
# Setup
numpy_mock.return_value = pd.Series([3, 2, 3])
data = pd.Series([3.0, 2.0, 3.0])
# Run
transformer = Mock()
transformer.nan = None
transformer._dtype = np.int
result = NumericalTransformer.reverse_transform(transformer, data)
# Asserts
expect = pd.Series([3.0, 2.0, 3.0])
expected_reverse_transform_call_count = 0
pd.testing.assert_series_equal(result, expect)
self.assertEqual(
transformer.null_transformer.reverse_transform.call_count,
expected_reverse_transform_call_count,
"NullTransformer.reverse_transform must be called at least once")
def test_reverse_transform_nan_ignore(self):
"""Test reverse_transform with nan equal to ignore"""
# Setup
data = pd.Series([1.5, None, 2.5])
# Run
transformer = Mock()
transformer.nan = None
transformer._dtype = np.float
result = NumericalTransformer.reverse_transform(transformer, data)
# Asserts
expect = pd.Series([1.5, None, 2.5])
expected_reverse_transform_call_count = 0
pd.testing.assert_series_equal(result, expect)
self.assertEqual(
transformer.null_transformer.reverse_transform.call_count,
expected_reverse_transform_call_count,
"NullTransformer.reverse_transform can't be called when nan is ignore"
)
class HyperTransformer:
"""HyperTransformer class.
The ``HyperTransformer`` class contains a collection of ``transformers`` that can be
used to transform and reverse transform one or more columns at once.
Args:
transformers (dict or None):
dict associating column names with transformers, which can be either passed
directly as an instance or as a dict specification. If ``None``, a simple
``transformers`` dict is built automatically from the data.
copy (bool):
Whether to make a copy of the input data or not. Defaults to ``True``.
anonymize (dict or None):
Dictionary specifying the names and ``faker`` categories of the categorical
columns that need to be anonymized. Defaults to ``None``.
dtypes (list or None):
List of column data types to use when building the ``transformers`` dict
automatically. If not passed, the ``DataFrame.dtypes`` are used.
dtype_transformers (dict or None):
Transformer templates to use for each dtype. Passed as a dictionary of
dtype kinds ('i', 'f', 'O', 'b', 'M') and transformer names, classes
or instances.
Example:
Create a simple ``HyperTransformer`` instance that will decide which transformers
to use based on the fit data ``dtypes``.
>>> ht = HyperTransformer()
Create a ``HyperTransformer`` passing a list of dtypes.
>>> ht = HyperTransformer(dtypes=[int, 'object', np.float64, 'datetime', 'bool'])
Create a ``HyperTransformer`` passing a ``transformers`` dict.
>>> transformers = {
... 'a': NumericalTransformer(dtype=float),
... 'b': {
... 'class': 'NumericalTransformer',
... 'kwargs': {
... 'dtype': int
... }
... }
... }
>>> ht = HyperTransformer(transformers)
"""
_TRANSFORMER_TEMPLATES = {
'numerical': NumericalTransformer,
'integer': NumericalTransformer(dtype=int),
'float': NumericalTransformer(dtype=float),
'categorical': CategoricalTransformer,
'categorical_fuzzy': CategoricalTransformer(fuzzy=True),
'one_hot_encoding': OneHotEncodingTransformer(error_on_unknown=False),
'label_encoding': LabelEncodingTransformer,
'boolean': BooleanTransformer,
'datetime': DatetimeTransformer,
}
_DTYPE_TRANSFORMERS = {
'i': 'numerical',
'f': 'numerical',
'O': 'categorical',
'b': 'boolean',
'M': 'datetime',
}
def __init__(self,
transformers=None,
copy=True,
anonymize=None,
dtypes=None,
dtype_transformers=None):
self.transformers = transformers
self._transformers = dict()
self.copy = copy
self.anonymize = anonymize or dict()
self.dtypes = dtypes
self.dtype_transformers = self._DTYPE_TRANSFORMERS.copy()
if dtype_transformers:
self.dtype_transformers.update(dtype_transformers)
def _analyze(self, data):
"""Build a ``dict`` with column names and transformers from a given ``pandas.DataFrame``.
When ``self.dtypes`` is ``None``, use the dtypes from the input data.
When ``dtype`` is:
- ``int``: a ``NumericalTransformer`` is created with ``dtype=int``.
- ``float``: a ``NumericalTransformer`` is created with ``dtype=float``.
- ``object`` or ``category``: a ``CategoricalTransformer`` is created.
- ``bool``: a ``BooleanTransformer`` is created.
- ``datetime``: a ``DatetimeTransformer`` is created.
Any other ``dtype`` is not supported and raises a ``ValueError``.
Args:
data (pandas.DataFrame):
Data used to analyze the ``pandas.DataFrame`` dtypes.
Returns:
dict:
Mapping of column names and transformer instances.
Raises:
ValueError:
if a ``dtype`` is not supported by the `HyperTransformer``.
"""
transformers = dict()
if self.dtypes:
dtypes = self.dtypes
else:
dtypes = [
data[column].dropna().infer_objects().dtype
for column in data.columns
]
for name, dtype in zip(data.columns, dtypes):
try:
kind = np.dtype(dtype).kind
except TypeError:
# probably category
kind = 'O'
transformer_template = self.dtype_transformers[kind]
if not transformer_template:
raise ValueError('Unsupported dtype: {}'.format(dtype))
if isinstance(transformer_template, str):
transformer_template = self._TRANSFORMER_TEMPLATES[
transformer_template]
if not isinstance(transformer_template, type):
transformer = deepcopy(transformer_template)
elif self.anonymize and transformer_template == CategoricalTransformer:
warnings.warn(
'Categorical anonymization is deprecated and will be removed from RDT soon.',
DeprecationWarning)
transformer = CategoricalTransformer(anonymize=self.anonymize)
else:
transformer = transformer_template()
transformers[name] = transformer
return transformers
def fit(self, data):
"""Fit the transformers to the data.
Args:
data (pandas.DataFrame):
Data to fit the transformers to.
"""
if self.transformers is not None:
self._transformers = load_transformers(self.transformers)
else:
self._transformers = self._analyze(data)
for column_name, transformer in self._transformers.items():
column = data[column_name]
transformer.fit(column)
def transform(self, data):
"""Transform the data.
If ``self.copy`` is ``True`` make a copy of the input data to avoid modifying it.
Args:
data (pandas.DataFrame):
Data to transform.
Returns:
pandas.DataFrame:
Transformed data.
"""
self.column_names = []
if self.copy:
data = data.copy()
for column_name, transformer in self._transformers.items():
column = data.pop(column_name)
transformed = transformer.transform(column)
self.column_names.append(column_name)
shape = transformed.shape
if len(shape) == 2:
for index in range(shape[1]):
new_column = '{}#{}'.format(column_name, index)
data[new_column] = transformed[:, index]
else:
data[column_name] = transformed
return data
def fit_transform(self, data):
"""Fit the transformers to the data and then transform it.
Args:
data (pandas.DataFrame):
Data to transform.
Returns:
pandas.DataFrame:
Transformed data.
"""
self.fit(data)
return self.transform(data)
@staticmethod
def _get_columns(data, column_name):
"""Get one or more columns that match a given name.
Args:
data (pandas.DataFrame):
Table to perform the matching.
column_name (str):
Name to match the columns.
Returns:
numpy.ndarray:
values of the matching columns
Raises:
ValueError:
if no columns match.
"""
regex = r'{}(#[0-9]+)?$'.format(re.escape(column_name))
columns = data.columns[data.columns.str.match(regex)]
if columns.empty:
raise ValueError('No columns match_ {}'.format(column_name))
values = [data.pop(column).values for column in columns]
if len(values) == 1:
return values[0]
return np.column_stack(values)
def reverse_transform(self, data):
"""Revert the transformations back to the original values.
Args:
data (pandas.DataFrame):
Data to revert.
Returns:
pandas.DataFrame:
reversed data.
"""
if self.copy:
data = data.copy()
for column_name, transformer in self._transformers.items():
columns = self._get_columns(data, column_name)
data[column_name] = transformer.reverse_transform(columns)
return data
