Function test_empty_str_methods

pandas/tests/strings/test_strings.py:157–237

(any_string_dtype)

def test_empty_str_methods(any_string_dtype):
    empty_str = empty = Series(dtype=any_string_dtype)
    empty_inferred_str = Series(dtype="str")
    if is_object_or_nan_string_dtype(any_string_dtype):
        empty_int = Series(dtype="int64")
        empty_bool = Series(dtype=bool)
    else:
        empty_int = Series(dtype="Int64")
        empty_bool = Series(dtype="boolean")
    empty_object = Series(dtype=object)
    empty_bytes = Series(dtype=object)
    empty_df = DataFrame()

    # GH7241
    # (extract) on empty series

    tm.assert_series_equal(empty_str, empty.str.cat(empty))
    assert "" == empty.str.cat()
    tm.assert_series_equal(empty_str, empty.str.title())
    tm.assert_series_equal(empty_int, empty.str.count("a"))
    tm.assert_series_equal(empty_bool, empty.str.contains("a"))
    tm.assert_series_equal(empty_bool, empty.str.startswith("a"))
    tm.assert_series_equal(empty_bool, empty.str.endswith("a"))
    tm.assert_series_equal(empty_str, empty.str.lower())
    tm.assert_series_equal(empty_str, empty.str.upper())
    tm.assert_series_equal(empty_str, empty.str.replace("a", "b"))
    tm.assert_series_equal(empty_str, empty.str.repeat(3))
    tm.assert_series_equal(empty_bool, empty.str.match("^a"))
    tm.assert_frame_equal(
        DataFrame(columns=range(1), dtype=any_string_dtype),
        empty.str.extract("()", expand=True),
    )
    tm.assert_frame_equal(
        DataFrame(columns=range(2), dtype=any_string_dtype),
        empty.str.extract("()()", expand=True),
    )
    tm.assert_series_equal(empty_str, empty.str.extract("()", expand=False))
    tm.assert_frame_equal(
        DataFrame(columns=range(2), dtype=any_string_dtype),
        empty.str.extract("()()", expand=False),
    )
    tm.assert_frame_equal(empty_df.set_axis([], axis=1), empty.str.get_dummies())
    tm.assert_series_equal(empty_str, empty_str.str.join(""))
    tm.assert_series_equal(empty_int, empty.str.len())
    tm.assert_series_equal(empty_object, empty_str.str.findall("a"))
    tm.assert_series_equal(empty_int, empty.str.find("a"))
    tm.assert_series_equal(empty_int, empty.str.rfind("a"))
    tm.assert_series_equal(empty_str, empty.str.pad(42))
    tm.assert_series_equal(empty_str, empty.str.center(42))
    tm.assert_series_equal(empty_object, empty.str.split("a"))
    tm.assert_series_equal(empty_object, empty.str.rsplit("a"))
    tm.assert_series_equal(empty_object, empty.str.partition("a", expand=False))
    tm.assert_frame_equal(empty_df, empty.str.partition("a"))
    tm.assert_series_equal(empty_object, empty.str.rpartition("a", expand=False))
    tm.assert_frame_equal(empty_df, empty.str.rpartition("a"))
    tm.assert_series_equal(empty_str, empty.str.slice(stop=1))
    tm.assert_series_equal(empty_str, empty.str.slice(step=1))
    tm.assert_series_equal(empty_str, empty.str.strip())