Function test_label_encoder

sklearn/preprocessing/tests/test_label.py:334–347

(values, classes, unknown)

    ids=["int64", "object", "str"],
)
def test_label_encoder(values, classes, unknown):
    # Test LabelEncoder's transform, fit_transform and
    # inverse_transform methods
    le = LabelEncoder()
    le.fit(values)
    assert_array_equal(le.classes_, classes)
    assert_array_equal(le.transform(values), [1, 0, 2, 0, 2])
    assert_array_equal(le.inverse_transform([1, 0, 2, 0, 2]), values)
    le = LabelEncoder()
    ret = le.fit_transform(values)
    assert_array_equal(ret, [1, 0, 2, 0, 2])

    with pytest.raises(ValueError, match="unseen labels"):
        le.transform(unknown)


def test_label_encoder_negative_ints():