def fit(self, X, y, **kwargs):
"""Fit encoder according to X and y.
Parameters
----------
X : array-like, shape = [n_samples, n_features]
Training vectors, where n_samples is the number of samples
and n_features is the number of features.
y : array-like, shape = [n_samples]
Target values.
Returns
-------
self : encoder
Returns self.
"""
# unite the input into pandas types
X = util.convert_input(X)
y = util.convert_input_vector(y, X.index).astype(float)
if X.shape[0] != y.shape[0]:
raise ValueError("The length of X is " + str(X.shape[0]) +
" but length of y is " + str(y.shape[0]) + ".")
self._dim = X.shape[1]
# if columns aren't passed, just use every string column
if self.use_default_cols:
self.cols = util.get_obj_cols(X)
else:
self.cols = util.convert_cols_to_list(self.cols)
if self.handle_missing == 'error':
if X[self.cols].isnull().any().any():
raise ValueError('Columns to be encoded can not contain null')
categories = self._fit(X, y, cols=self.cols)
self.mapping = categories
X_temp = self.transform(X, y, override_return_df=True)
self.feature_names = X_temp.columns.tolist()
if self.drop_invariant:
self.drop_cols = []
generated_cols = util.get_generated_cols(X, X_temp, self.cols)
self.drop_cols = [
x for x in generated_cols if X_temp[x].var() <= 10e-5
]
try:
[self.feature_names.remove(x) for x in self.drop_cols]
except KeyError as e:
if self.verbose > 0:
print("Could not remove column from feature names."
"Not found in generated cols.\n{}".format(e))
return self
def transform(self, X, y=None, override_return_df=False):
"""Perform the transformation to new categorical data.
Parameters
----------
X : array-like, shape = [n_samples, n_features]
y : array-like, shape = [n_samples] when transform by leave one out
None, when transform without target information (such as transform test set)
Returns
-------
p : array, shape = [n_samples, n_numeric + N]
Transformed values with encoding applied.
"""
if self.handle_missing == 'error':
if X[self.cols].isnull().any().any():
raise ValueError('Columns to be encoded can not contain null')
if self._dim is None:
raise ValueError(
'Must train encoder before it can be used to transform data.')
# unite the input into pandas types
X = util.convert_input(X)
# then make sure that it is the right size
if X.shape[1] != self._dim:
raise ValueError('Unexpected input dimension %d, expected %d' % (
X.shape[1],
self._dim,
))
# if we are encoding the training data, we have to check the target
if y is not None:
y = util.convert_input_vector(y, X.index).astype(float)
if X.shape[0] != y.shape[0]:
raise ValueError("The length of X is " + str(X.shape[0]) +
" but length of y is " + str(y.shape[0]) +
".")
if not self.cols:
return X
X = self._transform(X, y, mapping=self.mapping)
if self.drop_invariant:
for col in self.drop_cols:
X.drop(col, 1, inplace=True)
if self.return_df or override_return_df:
return X
else:
return X.values
def transform(self, X, y=None, override_return_df=False):
"""Perform the transformation to new categorical data. When the data are used for model training,
it is important to also pass the target in order to apply leave one out.
Parameters
----------
X : array-like, shape = [n_samples, n_features]
y : array-like, shape = [n_samples] when transform by leave one out
None, when transform without target information (such as transform test set)
Returns
-------
p : array, shape = [n_samples, n_numeric + N]
Transformed values with encoding applied.
"""
if self.handle_missing == 'error':
if X[self.cols].isnull().any().any():
raise ValueError('Columns to be encoded can not contain null')
if self._dim is None:
raise ValueError(
'Must train encoder before it can be used to transform data.')
# Unite the input into pandas types
X = util.convert_input(X)
# Then make sure that it is the right size
if X.shape[1] != self._dim:
raise ValueError('Unexpected input dimension %d, expected %d' % (
X.shape[1],
self._dim,
))
# If we are encoding the training data, we have to check the target
if y is not None:
y = util.convert_input_vector(y, X.index).astype(float)
if X.shape[0] != y.shape[0]:
raise ValueError("The length of X is " + str(X.shape[0]) +
" but length of y is " + str(y.shape[0]) +
".")
if not self.cols:
return X
# Do not modify the input argument
X = X.copy(deep=True)
X = self.ordinal_encoder.transform(X)
if self.handle_unknown == 'error':
if X[self.cols].isin([-1]).any().any():
raise ValueError('Unexpected categories found in dataframe')
# Loop over columns and replace nominal values with WOE
X = self._score(X, y)
# Postprocessing
# Note: We should not even convert these columns.
if self.drop_invariant:
for col in self.drop_cols:
X.drop(col, 1, inplace=True)
if self.return_df or override_return_df:
return X
else:
return X.values
def fit(self, X, y, **kwargs):
"""Fit encoder according to X and binary y.
Parameters
----------
X : array-like, shape = [n_samples, n_features]
Training vectors, where n_samples is the number of samples
and n_features is the number of features.
y : array-like, shape = [n_samples]
Binary target values.
Returns
-------
self : encoder
Returns self.
"""
# Unite parameters into pandas types
X = util.convert_input(X)
y = util.convert_input_vector(y, X.index).astype(float)
# The lengths must be equal
if X.shape[0] != y.shape[0]:
raise ValueError("The length of X is " + str(X.shape[0]) +
" but length of y is " + str(y.shape[0]) + ".")
self._dim = X.shape[1]
# If columns aren't passed, just use every string column
if self.cols is None:
self.cols = util.get_obj_cols(X)
else:
self.cols = util.convert_cols_to_list(self.cols)
if self.handle_missing == 'error':
if X[self.cols].isnull().any().any():
raise ValueError('Columns to be encoded can not contain null')
self.ordinal_encoder = OrdinalEncoder(verbose=self.verbose,
cols=self.cols,
handle_unknown='value',
handle_missing='value')
self.ordinal_encoder = self.ordinal_encoder.fit(X)
X_ordinal = self.ordinal_encoder.transform(X)
# Training
if self.model == 'independent':
self.mapping = self._train_independent(X_ordinal, y)
elif self.model == 'pooled':
self.mapping = self._train_pooled(X_ordinal, y)
elif self.model == 'beta':
self.mapping = self._train_beta(X_ordinal, y)
elif self.model == 'binary':
# The label must be binary with values {0,1}
unique = y.unique()
if len(unique) != 2:
raise ValueError(
"The target column y must be binary. But the target contains "
+ str(len(unique)) + " unique value(s).")
if y.isnull().any():
raise ValueError(
"The target column y must not contain missing values.")
if np.max(unique) < 1:
raise ValueError(
"The target column y must be binary with values {0, 1}. Value 1 was not found in the target."
)
if np.min(unique) > 0:
raise ValueError(
"The target column y must be binary with values {0, 1}. Value 0 was not found in the target."
)
# Perform the training
self.mapping = self._train_log_odds_ratio(X_ordinal, y)
else:
raise ValueError("model='" + str(self.model) +
"' is not a recognized option")
X_temp = self.transform(X, override_return_df=True)
self.feature_names = X_temp.columns.tolist()
# Store column names with approximately constant variance on the training data
if self.drop_invariant:
self.drop_cols = []
generated_cols = util.get_generated_cols(X, X_temp, self.cols)
self.drop_cols = [
x for x in generated_cols if X_temp[x].var() <= 10e-5
]
try:
[self.feature_names.remove(x) for x in self.drop_cols]
except KeyError as e:
if self.verbose > 0:
print("Could not remove column from feature names."
"Not found in generated cols.\n{}".format(e))
return self
