def test_argsort_stable(self):
s = Series(np.random.randint(0, 100, size=10000))
mindexer = s.argsort(kind="mergesort")
qindexer = s.argsort()
mexpected = np.argsort(s.values, kind="mergesort")
qexpected = np.argsort(s.values, kind="quicksort")
tm.assert_series_equal(mindexer, Series(mexpected), check_dtype=False)
tm.assert_series_equal(qindexer, Series(qexpected), check_dtype=False)
msg = (r"ndarray Expected type <class 'numpy\.ndarray'>, "
r"found <class 'pandas\.core\.series\.Series'> instead")
with pytest.raises(AssertionError, match=msg):
tm.assert_numpy_array_equal(qindexer, mindexer)
def test_argsort(self, datetime_series):
self._check_accum_op("argsort", datetime_series, check_dtype=False)
argsorted = datetime_series.argsort()
assert issubclass(argsorted.dtype.type, np.integer)
# GH 2967 (introduced bug in 0.11-dev I think)
s = Series([Timestamp("201301{i:02d}".format(i=i)) for i in range(1, 6)])
assert s.dtype == "datetime64[ns]"
shifted = s.shift(-1)
assert shifted.dtype == "datetime64[ns]"
assert isna(shifted[4])
result = s.argsort()
expected = Series(range(5), dtype="int64")
tm.assert_series_equal(result, expected)
result = shifted.argsort()
expected = Series(list(range(4)) + [-1], dtype="int64")
tm.assert_series_equal(result, expected)
