29 lines
971 B
Python
29 lines
971 B
Python
from sklearn.utils.testing import (assert_array_equal, assert_equal,
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assert_raises)
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from scipy.sparse import bsr_matrix, csc_matrix, csr_matrix
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from sklearn.feature_selection import VarianceThreshold
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data = [[0, 1, 2, 3, 4],
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[0, 2, 2, 3, 5],
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[1, 1, 2, 4, 0]]
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def test_zero_variance():
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# Test VarianceThreshold with default setting, zero variance.
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for X in [data, csr_matrix(data), csc_matrix(data), bsr_matrix(data)]:
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sel = VarianceThreshold().fit(X)
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assert_array_equal([0, 1, 3, 4], sel.get_support(indices=True))
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assert_raises(ValueError, VarianceThreshold().fit, [[0, 1, 2, 3]])
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assert_raises(ValueError, VarianceThreshold().fit, [[0, 1], [0, 1]])
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def test_variance_threshold():
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# Test VarianceThreshold with custom variance.
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for X in [data, csr_matrix(data)]:
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X = VarianceThreshold(threshold=.4).fit_transform(X)
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assert_equal((len(data), 1), X.shape)
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