def test_column_transformer_invalid_columns(remainder):
X_array = np.array([[0, 1, 2], [2, 4, 6]]).T
# general invalid
for col in [1.5, ['string', 1], slice(1, 's'), np.array([1.])]:
ct = ColumnTransformer([('trans', Trans(), col)], remainder=remainder)
assert_raise_message(ValueError, "No valid specification", ct.fit,
X_array)
# invalid for arrays
for col in ['string', ['string', 'other'], slice('a', 'b')]:
ct = ColumnTransformer([('trans', Trans(), col)], remainder=remainder)
assert_raise_message(ValueError, "Specifying the columns", ct.fit,
X_array)
# transformed n_features does not match fitted n_features
col = [0, 1]
ct = ColumnTransformer([('trans', Trans(), col)], remainder=remainder)
ct.fit(X_array)
X_array_more = np.array([[0, 1, 2], [2, 4, 6], [3, 6, 9]]).T
msg = ("Given feature/column names or counts do not match the ones for "
"the data given during fit.")
with pytest.warns(DeprecationWarning, match=msg):
ct.transform(X_array_more) # Should accept added columns, for now
X_array_fewer = np.array([
[0, 1, 2],
]).T
err_msg = 'Number of features'
with pytest.raises(ValueError, match=err_msg):
ct.transform(X_array_fewer)
def test_column_transformer_callable_specifier():
# assert that function gets the full array / dataframe
X_array = np.array([[0, 1, 2], [2, 4, 6]]).T
X_res_first = np.array([[0, 1, 2]]).T
def func(X):
assert_array_equal(X, X_array)
return [0]
ct = ColumnTransformer([('trans', Trans(), func)], remainder='drop')
assert_array_equal(ct.fit_transform(X_array), X_res_first)
assert_array_equal(ct.fit(X_array).transform(X_array), X_res_first)
assert callable(ct.transformers[0][2])
assert ct.transformers_[0][2] == [0]
pd = pytest.importorskip('pandas')
X_df = pd.DataFrame(X_array, columns=['first', 'second'])
def func(X):
assert_array_equal(X.columns, X_df.columns)
assert_array_equal(X.values, X_df.values)
return ['first']
ct = ColumnTransformer([('trans', Trans(), func)], remainder='drop')
assert_array_equal(ct.fit_transform(X_df), X_res_first)
assert_array_equal(ct.fit(X_df).transform(X_df), X_res_first)
assert callable(ct.transformers[0][2])
assert ct.transformers_[0][2] == ['first']
def test_column_transformer():
X_array = np.array([[0, 1, 2], [2, 4, 6]]).T
X_res_first1D = np.array([0, 1, 2])
X_res_second1D = np.array([2, 4, 6])
X_res_first = X_res_first1D.reshape(-1, 1)
X_res_both = X_array
cases = [
# single column 1D / 2D
(0, X_res_first),
([0], X_res_first),
# list-like
([0, 1], X_res_both),
(np.array([0, 1]), X_res_both),
# slice
(slice(0, 1), X_res_first),
(slice(0, 2), X_res_both),
# boolean mask
(np.array([True, False]), X_res_first),
]
for selection, res in cases:
ct = ColumnTransformer([('trans', Trans(), selection)],
remainder='drop')
assert_array_equal(ct.fit_transform(X_array), res)
assert_array_equal(ct.fit(X_array).transform(X_array), res)
# callable that returns any of the allowed specifiers
ct = ColumnTransformer([('trans', Trans(), lambda x: selection)],
remainder='drop')
assert_array_equal(ct.fit_transform(X_array), res)
assert_array_equal(ct.fit(X_array).transform(X_array), res)
ct = ColumnTransformer([('trans1', Trans(), [0]),
('trans2', Trans(), [1])])
assert_array_equal(ct.fit_transform(X_array), X_res_both)
assert_array_equal(ct.fit(X_array).transform(X_array), X_res_both)
assert len(ct.transformers_) == 2
# test with transformer_weights
transformer_weights = {'trans1': .1, 'trans2': 10}
both = ColumnTransformer([('trans1', Trans(), [0]),
('trans2', Trans(), [1])],
transformer_weights=transformer_weights)
res = np.vstack([
transformer_weights['trans1'] * X_res_first1D,
transformer_weights['trans2'] * X_res_second1D
]).T
assert_array_equal(both.fit_transform(X_array), res)
assert_array_equal(both.fit(X_array).transform(X_array), res)
assert len(both.transformers_) == 2
both = ColumnTransformer([('trans', Trans(), [0, 1])],
transformer_weights={'trans': .1})
assert_array_equal(both.fit_transform(X_array), 0.1 * X_res_both)
assert_array_equal(both.fit(X_array).transform(X_array), 0.1 * X_res_both)
assert len(both.transformers_) == 1
def test_column_transformer_remainder():
X_array = np.array([[0, 1, 2], [2, 4, 6]]).T
X_res_first = np.array([0, 1, 2]).reshape(-1, 1)
X_res_second = np.array([2, 4, 6]).reshape(-1, 1)
X_res_both = X_array
# default drop
ct = ColumnTransformer([('trans1', Trans(), [0])])
assert_array_equal(ct.fit_transform(X_array), X_res_first)
assert_array_equal(ct.fit(X_array).transform(X_array), X_res_first)
assert len(ct.transformers_) == 2
assert ct.transformers_[-1][0] == 'remainder'
assert ct.transformers_[-1][1] == 'drop'
assert_array_equal(ct.transformers_[-1][2], [1])
# specify passthrough
ct = ColumnTransformer([('trans', Trans(), [0])], remainder='passthrough')
assert_array_equal(ct.fit_transform(X_array), X_res_both)
assert_array_equal(ct.fit(X_array).transform(X_array), X_res_both)
assert len(ct.transformers_) == 2
assert ct.transformers_[-1][0] == 'remainder'
assert ct.transformers_[-1][1] == 'passthrough'
assert_array_equal(ct.transformers_[-1][2], [1])
# column order is not preserved (passed through added to end)
ct = ColumnTransformer([('trans1', Trans(), [1])], remainder='passthrough')
assert_array_equal(ct.fit_transform(X_array), X_res_both[:, ::-1])
assert_array_equal(ct.fit(X_array).transform(X_array), X_res_both[:, ::-1])
assert len(ct.transformers_) == 2
assert ct.transformers_[-1][0] == 'remainder'
assert ct.transformers_[-1][1] == 'passthrough'
assert_array_equal(ct.transformers_[-1][2], [0])
# passthrough when all actual transformers are skipped
ct = ColumnTransformer([('trans1', 'drop', [0])], remainder='passthrough')
assert_array_equal(ct.fit_transform(X_array), X_res_second)
assert_array_equal(ct.fit(X_array).transform(X_array), X_res_second)
assert len(ct.transformers_) == 2
assert ct.transformers_[-1][0] == 'remainder'
assert ct.transformers_[-1][1] == 'passthrough'
assert_array_equal(ct.transformers_[-1][2], [1])
# error on invalid arg
ct = ColumnTransformer([('trans1', Trans(), [0])], remainder=1)
assert_raise_message(
ValueError,
"remainder keyword needs to be one of \'drop\', \'passthrough\', "
"or estimator.", ct.fit, X_array)
assert_raise_message(
ValueError,
"remainder keyword needs to be one of \'drop\', \'passthrough\', "
"or estimator.", ct.fit_transform, X_array)
# check default for make_column_transformer
ct = make_column_transformer((Trans(), [0]))
assert ct.remainder == 'drop'
def test_column_transformer_cloning():
X_array = np.array([[0., 1., 2.], [2., 4., 6.]]).T
ct = ColumnTransformer([('trans', StandardScaler(), [0])])
ct.fit(X_array)
assert not hasattr(ct.transformers[0][1], 'mean_')
assert hasattr(ct.transformers_[0][1], 'mean_')
ct = ColumnTransformer([('trans', StandardScaler(), [0])])
ct.fit_transform(X_array)
assert not hasattr(ct.transformers[0][1], 'mean_')
assert hasattr(ct.transformers_[0][1], 'mean_')
def test_column_transformer_named_estimators():
X_array = np.array([[0., 1., 2.], [2., 4., 6.]]).T
ct = ColumnTransformer([('trans1', StandardScaler(), [0]),
('trans2', StandardScaler(with_std=False), [1])])
assert not hasattr(ct, 'transformers_')
ct.fit(X_array)
assert hasattr(ct, 'transformers_')
assert isinstance(ct.named_transformers_['trans1'], StandardScaler)
assert isinstance(ct.named_transformers_.trans1, StandardScaler)
assert isinstance(ct.named_transformers_['trans2'], StandardScaler)
assert isinstance(ct.named_transformers_.trans2, StandardScaler)
assert not ct.named_transformers_.trans2.with_std
# check it are fitted transformers
assert ct.named_transformers_.trans1.mean_ == 1.
def test_column_transformer_get_feature_names():
X_array = np.array([[0., 1., 2.], [2., 4., 6.]]).T
ct = ColumnTransformer([('trans', Trans(), [0, 1])])
# raise correct error when not fitted
with pytest.raises(NotFittedError):
ct.get_feature_names()
# raise correct error when no feature names are available
ct.fit(X_array)
assert_raise_message(
AttributeError, "Transformer trans (type Trans) does not provide "
"get_feature_names", ct.get_feature_names)
# working example
X = np.array([[{
'a': 1,
'b': 2
}, {
'a': 3,
'b': 4
}], [{
'c': 5
}, {
'c': 6
}]],
dtype=object).T
ct = ColumnTransformer([('col' + str(i), DictVectorizer(), i)
for i in range(2)])
ct.fit(X)
assert ct.get_feature_names() == ['col0__a', 'col0__b', 'col1__c']
# passthrough transformers not supported
ct = ColumnTransformer([('trans', 'passthrough', [0, 1])])
ct.fit(X)
assert_raise_message(NotImplementedError,
'get_feature_names is not yet supported',
ct.get_feature_names)
ct = ColumnTransformer([('trans', DictVectorizer(), 0)],
remainder='passthrough')
ct.fit(X)
assert_raise_message(NotImplementedError,
'get_feature_names is not yet supported',
ct.get_feature_names)
# drop transformer
ct = ColumnTransformer([('col0', DictVectorizer(), 0),
('col1', 'drop', 1)])
ct.fit(X)
assert ct.get_feature_names() == ['col0__a', 'col0__b']
def test_feature_name_validation():
"""Tests if the proper warning/error is raised if the columns do not match
during fit and transform."""
pd = pytest.importorskip("pandas")
X = np.ones(shape=(3, 2))
X_extra = np.ones(shape=(3, 3))
df = pd.DataFrame(X, columns=['a', 'b'])
df_extra = pd.DataFrame(X_extra, columns=['a', 'b', 'c'])
tf = ColumnTransformer([('bycol', Trans(), ['a', 'b'])])
tf.fit(df)
msg = ("Given feature/column names or counts do not match the ones for "
"the data given during fit.")
with pytest.warns(DeprecationWarning, match=msg):
tf.transform(df_extra)
tf = ColumnTransformer([('bycol', Trans(), [0])])
tf.fit(df)
with pytest.warns(DeprecationWarning, match=msg):
tf.transform(X_extra)
with warnings.catch_warnings(record=True) as warns:
tf.transform(X)
assert not warns
tf = ColumnTransformer([('bycol', Trans(), ['a'])], remainder=Trans())
tf.fit(df)
with pytest.warns(DeprecationWarning, match=msg):
tf.transform(df_extra)
tf = ColumnTransformer([('bycol', Trans(), [0, -1])])
tf.fit(df)
msg = "At least one negative column was used to"
with pytest.raises(RuntimeError, match=msg):
tf.transform(df_extra)
tf = ColumnTransformer([('bycol', Trans(), slice(-1, -3, -1))])
tf.fit(df)
with pytest.raises(RuntimeError, match=msg):
tf.transform(df_extra)
with warnings.catch_warnings(record=True) as warns:
tf.transform(df)
assert not warns
def test_column_transformer_no_remaining_remainder_transformer():
X_array = np.array([[0, 1, 2], [2, 4, 6], [8, 6, 4]]).T
ct = ColumnTransformer([('trans1', Trans(), [0, 1, 2])],
remainder=DoubleTrans())
assert_array_equal(ct.fit_transform(X_array), X_array)
assert_array_equal(ct.fit(X_array).transform(X_array), X_array)
assert len(ct.transformers_) == 1
assert ct.transformers_[-1][0] != 'remainder'
def test_column_transformer_remainder_numpy(key):
# test different ways that columns are specified with passthrough
X_array = np.array([[0, 1, 2], [2, 4, 6]]).T
X_res_both = X_array
ct = ColumnTransformer([('trans1', Trans(), key)], remainder='passthrough')
assert_array_equal(ct.fit_transform(X_array), X_res_both)
assert_array_equal(ct.fit(X_array).transform(X_array), X_res_both)
assert len(ct.transformers_) == 2
assert ct.transformers_[-1][0] == 'remainder'
assert ct.transformers_[-1][1] == 'passthrough'
assert_array_equal(ct.transformers_[-1][2], [1])
def test_column_transformer_sparse_stacking():
X_array = np.array([[0, 1, 2], [2, 4, 6]]).T
col_trans = ColumnTransformer([('trans1', Trans(), [0]),
('trans2', SparseMatrixTrans(), 1)],
sparse_threshold=0.8)
col_trans.fit(X_array)
X_trans = col_trans.transform(X_array)
assert sparse.issparse(X_trans)
assert X_trans.shape == (X_trans.shape[0], X_trans.shape[0] + 1)
assert_array_equal(X_trans.toarray()[:, 1:], np.eye(X_trans.shape[0]))
assert len(col_trans.transformers_) == 2
assert col_trans.transformers_[-1][0] != 'remainder'
col_trans = ColumnTransformer([('trans1', Trans(), [0]),
('trans2', SparseMatrixTrans(), 1)],
sparse_threshold=0.1)
col_trans.fit(X_array)
X_trans = col_trans.transform(X_array)
assert not sparse.issparse(X_trans)
assert X_trans.shape == (X_trans.shape[0], X_trans.shape[0] + 1)
assert_array_equal(X_trans[:, 1:], np.eye(X_trans.shape[0]))
def test_column_transformer_empty_columns(pandas, column):
# test case that ensures that the column transformer does also work when
# a given transformer doesn't have any columns to work on
X_array = np.array([[0, 1, 2], [2, 4, 6]]).T
X_res_both = X_array
if pandas:
pd = pytest.importorskip('pandas')
X = pd.DataFrame(X_array, columns=['first', 'second'])
else:
X = X_array
ct = ColumnTransformer([('trans1', Trans(), [0, 1]),
('trans2', Trans(), column)])
assert_array_equal(ct.fit_transform(X), X_res_both)
assert_array_equal(ct.fit(X).transform(X), X_res_both)
assert len(ct.transformers_) == 2
assert isinstance(ct.transformers_[1][1], Trans)
ct = ColumnTransformer([('trans1', Trans(), column),
('trans2', Trans(), [0, 1])])
assert_array_equal(ct.fit_transform(X), X_res_both)
assert_array_equal(ct.fit(X).transform(X), X_res_both)
assert len(ct.transformers_) == 2
assert isinstance(ct.transformers_[0][1], Trans)
ct = ColumnTransformer([('trans', Trans(), column)],
remainder='passthrough')
assert_array_equal(ct.fit_transform(X), X_res_both)
assert_array_equal(ct.fit(X).transform(X), X_res_both)
assert len(ct.transformers_) == 2 # including remainder
assert isinstance(ct.transformers_[0][1], Trans)
fixture = np.array([[], [], []])
ct = ColumnTransformer([('trans', Trans(), column)], remainder='drop')
assert_array_equal(ct.fit_transform(X), fixture)
assert_array_equal(ct.fit(X).transform(X), fixture)
assert len(ct.transformers_) == 2 # including remainder
assert isinstance(ct.transformers_[0][1], Trans)
def test_column_transformer_drops_all_remainder_transformer():
X_array = np.array([[0, 1, 2], [2, 4, 6], [8, 6, 4]]).T
# columns are doubled when remainder = DoubleTrans
X_res_both = 2 * X_array.copy()[:, 1:3]
ct = ColumnTransformer([('trans1', 'drop', [0])], remainder=DoubleTrans())
assert_array_equal(ct.fit_transform(X_array), X_res_both)
assert_array_equal(ct.fit(X_array).transform(X_array), X_res_both)
assert len(ct.transformers_) == 2
assert ct.transformers_[-1][0] == 'remainder'
assert isinstance(ct.transformers_[-1][1], DoubleTrans)
assert_array_equal(ct.transformers_[-1][2], [1, 2])
def test_column_transformer_list():
X_list = [[1, float('nan'), 'a'], [0, 0, 'b']]
expected_result = np.array([
[1, float('nan'), 1, 0],
[-1, 0, 0, 1],
])
ct = ColumnTransformer([
('numerical', StandardScaler(), [0, 1]),
('categorical', OneHotEncoder(), [2]),
])
assert_array_equal(ct.fit_transform(X_list), expected_result)
assert_array_equal(ct.fit(X_list).transform(X_list), expected_result)
def test_column_transformer_reordered_column_names_remainder(explicit_colname):
"""Regression test for issue #14223: 'Named col indexing fails with
ColumnTransformer remainder on changing DataFrame column ordering'
Should raise error on changed order combined with remainder.
Should allow for added columns in `transform` input DataFrame
as long as all preceding columns match.
"""
pd = pytest.importorskip('pandas')
X_fit_array = np.array([[0, 1, 2], [2, 4, 6]]).T
X_fit_df = pd.DataFrame(X_fit_array, columns=['first', 'second'])
X_trans_array = np.array([[2, 4, 6], [0, 1, 2]]).T
X_trans_df = pd.DataFrame(X_trans_array, columns=['second', 'first'])
tf = ColumnTransformer([('bycol', Trans(), explicit_colname)],
remainder=Trans())
tf.fit(X_fit_df)
err_msg = 'Column ordering must be equal'
warn_msg = ("Given feature/column names or counts do not match the ones "
"for the data given during fit.")
with pytest.raises(ValueError, match=err_msg):
tf.transform(X_trans_df)
# No error for added columns if ordering is identical
X_extended_df = X_fit_df.copy()
X_extended_df['third'] = [3, 6, 9]
with pytest.warns(DeprecationWarning, match=warn_msg):
tf.transform(X_extended_df) # No error should be raised, for now
# No 'columns' AttributeError when transform input is a numpy array
X_array = X_fit_array.copy()
err_msg = 'Specifying the columns'
with pytest.raises(ValueError, match=err_msg):
tf.transform(X_array)
def test_column_transformer_remainder_transformer(key):
X_array = np.array([[0, 1, 2], [2, 4, 6], [8, 6, 4]]).T
X_res_both = X_array.copy()
# second and third columns are doubled when remainder = DoubleTrans
X_res_both[:, 1:3] *= 2
ct = ColumnTransformer([('trans1', Trans(), key)], remainder=DoubleTrans())
assert_array_equal(ct.fit_transform(X_array), X_res_both)
assert_array_equal(ct.fit(X_array).transform(X_array), X_res_both)
assert len(ct.transformers_) == 2
assert ct.transformers_[-1][0] == 'remainder'
assert isinstance(ct.transformers_[-1][1], DoubleTrans)
assert_array_equal(ct.transformers_[-1][2], [1, 2])
def test_column_transformer_special_strings():
# one 'drop' -> ignore
X_array = np.array([[0., 1., 2.], [2., 4., 6.]]).T
ct = ColumnTransformer([('trans1', Trans(), [0]), ('trans2', 'drop', [1])])
exp = np.array([[0.], [1.], [2.]])
assert_array_equal(ct.fit_transform(X_array), exp)
assert_array_equal(ct.fit(X_array).transform(X_array), exp)
assert len(ct.transformers_) == 2
assert ct.transformers_[-1][0] != 'remainder'
# all 'drop' -> return shape 0 array
ct = ColumnTransformer([('trans1', 'drop', [0]), ('trans2', 'drop', [1])])
assert_array_equal(ct.fit(X_array).transform(X_array).shape, (3, 0))
assert_array_equal(ct.fit_transform(X_array).shape, (3, 0))
assert len(ct.transformers_) == 2
assert ct.transformers_[-1][0] != 'remainder'
# 'passthrough'
X_array = np.array([[0., 1., 2.], [2., 4., 6.]]).T
ct = ColumnTransformer([('trans1', Trans(), [0]),
('trans2', 'passthrough', [1])])
exp = X_array
assert_array_equal(ct.fit_transform(X_array), exp)
assert_array_equal(ct.fit(X_array).transform(X_array), exp)
assert len(ct.transformers_) == 2
assert ct.transformers_[-1][0] != 'remainder'
# None itself / other string is not valid
for val in [None, 'other']:
ct = ColumnTransformer([('trans1', Trans(), [0]),
('trans2', None, [1])])
assert_raise_message(TypeError, "All estimators should implement",
ct.fit_transform, X_array)
assert_raise_message(TypeError, "All estimators should implement",
ct.fit, X_array)
def test_column_transformer_sparse_array():
X_sparse = sparse.eye(3, 2).tocsr()
# no distinction between 1D and 2D
X_res_first = X_sparse[:, 0]
X_res_both = X_sparse
for col in [0, [0], slice(0, 1)]:
for remainder, res in [('drop', X_res_first),
('passthrough', X_res_both)]:
ct = ColumnTransformer([('trans', Trans(), col)],
remainder=remainder,
sparse_threshold=0.8)
assert sparse.issparse(ct.fit_transform(X_sparse))
assert_allclose_dense_sparse(ct.fit_transform(X_sparse), res)
assert_allclose_dense_sparse(
ct.fit(X_sparse).transform(X_sparse), res)
for col in [[0, 1], slice(0, 2)]:
ct = ColumnTransformer([('trans', Trans(), col)], sparse_threshold=0.8)
assert sparse.issparse(ct.fit_transform(X_sparse))
assert_allclose_dense_sparse(ct.fit_transform(X_sparse), X_res_both)
assert_allclose_dense_sparse(
ct.fit(X_sparse).transform(X_sparse), X_res_both)
def test_column_transformer_remainder_pandas(key):
# test different ways that columns are specified with passthrough
pd = pytest.importorskip('pandas')
if isinstance(key, str) and key == 'pd-index':
key = pd.Index(['first'])
X_array = np.array([[0, 1, 2], [2, 4, 6]]).T
X_df = pd.DataFrame(X_array, columns=['first', 'second'])
X_res_both = X_array
ct = ColumnTransformer([('trans1', Trans(), key)], remainder='passthrough')
assert_array_equal(ct.fit_transform(X_df), X_res_both)
assert_array_equal(ct.fit(X_df).transform(X_df), X_res_both)
assert len(ct.transformers_) == 2
assert ct.transformers_[-1][0] == 'remainder'
assert ct.transformers_[-1][1] == 'passthrough'
assert_array_equal(ct.transformers_[-1][2], [1])
def test_column_transformer_dataframe():
pd = pytest.importorskip('pandas')
X_array = np.array([[0, 1, 2], [2, 4, 6]]).T
X_df = pd.DataFrame(X_array, columns=['first', 'second'])
X_res_first = np.array([0, 1, 2]).reshape(-1, 1)
X_res_both = X_array
cases = [
# String keys: label based
# scalar
('first', X_res_first),
# list
(['first'], X_res_first),
(['first', 'second'], X_res_both),
# slice
(slice('first', 'second'), X_res_both),
# int keys: positional
# scalar
(0, X_res_first),
# list
([0], X_res_first),
([0, 1], X_res_both),
(np.array([0, 1]), X_res_both),
# slice
(slice(0, 1), X_res_first),
(slice(0, 2), X_res_both),
# boolean mask
(np.array([True, False]), X_res_first),
(pd.Series([True, False], index=['first', 'second']), X_res_first),
]
for selection, res in cases:
ct = ColumnTransformer([('trans', Trans(), selection)],
remainder='drop')
assert_array_equal(ct.fit_transform(X_df), res)
assert_array_equal(ct.fit(X_df).transform(X_df), res)
# callable that returns any of the allowed specifiers
ct = ColumnTransformer([('trans', Trans(), lambda X: selection)],
remainder='drop')
assert_array_equal(ct.fit_transform(X_df), res)
assert_array_equal(ct.fit(X_df).transform(X_df), res)
ct = ColumnTransformer([('trans1', Trans(), ['first']),
('trans2', Trans(), ['second'])])
assert_array_equal(ct.fit_transform(X_df), X_res_both)
assert_array_equal(ct.fit(X_df).transform(X_df), X_res_both)
assert len(ct.transformers_) == 2
assert ct.transformers_[-1][0] != 'remainder'
ct = ColumnTransformer([('trans1', Trans(), [0]),
('trans2', Trans(), [1])])
assert_array_equal(ct.fit_transform(X_df), X_res_both)
assert_array_equal(ct.fit(X_df).transform(X_df), X_res_both)
assert len(ct.transformers_) == 2
assert ct.transformers_[-1][0] != 'remainder'
# test with transformer_weights
transformer_weights = {'trans1': .1, 'trans2': 10}
both = ColumnTransformer([('trans1', Trans(), ['first']),
('trans2', Trans(), ['second'])],
transformer_weights=transformer_weights)
res = np.vstack([
transformer_weights['trans1'] * X_df['first'],
transformer_weights['trans2'] * X_df['second']
]).T
assert_array_equal(both.fit_transform(X_df), res)
assert_array_equal(both.fit(X_df).transform(X_df), res)
assert len(both.transformers_) == 2
assert ct.transformers_[-1][0] != 'remainder'
# test multiple columns
both = ColumnTransformer([('trans', Trans(), ['first', 'second'])],
transformer_weights={'trans': .1})
assert_array_equal(both.fit_transform(X_df), 0.1 * X_res_both)
assert_array_equal(both.fit(X_df).transform(X_df), 0.1 * X_res_both)
assert len(both.transformers_) == 1
assert ct.transformers_[-1][0] != 'remainder'
both = ColumnTransformer([('trans', Trans(), [0, 1])],
transformer_weights={'trans': .1})
assert_array_equal(both.fit_transform(X_df), 0.1 * X_res_both)
assert_array_equal(both.fit(X_df).transform(X_df), 0.1 * X_res_both)
assert len(both.transformers_) == 1
assert ct.transformers_[-1][0] != 'remainder'
# ensure pandas object is passes through
class TransAssert(BaseEstimator):
def fit(self, X, y=None):
return self
def transform(self, X, y=None):
assert isinstance(X, (pd.DataFrame, pd.Series))
if isinstance(X, pd.Series):
X = X.to_frame()
return X
ct = ColumnTransformer([('trans', TransAssert(), 'first')],
remainder='drop')
ct.fit_transform(X_df)
ct = ColumnTransformer([('trans', TransAssert(), ['first', 'second'])])
ct.fit_transform(X_df)
# integer column spec + integer column names -> still use positional
X_df2 = X_df.copy()
X_df2.columns = [1, 0]
ct = ColumnTransformer([('trans', Trans(), 0)], remainder='drop')
assert_array_equal(ct.fit_transform(X_df2), X_res_first)
assert_array_equal(ct.fit(X_df2).transform(X_df2), X_res_first)
assert len(ct.transformers_) == 2
assert ct.transformers_[-1][0] == 'remainder'
assert ct.transformers_[-1][1] == 'drop'
assert_array_equal(ct.transformers_[-1][2], [1])