diff options
| -rw-r--r-- | numpy/ma/core.py | 4 | ||||
| -rw-r--r-- | numpy/ma/tests/test_core.py | 11 |
2 files changed, 14 insertions, 1 deletions
diff --git a/numpy/ma/core.py b/numpy/ma/core.py index 14dc21804..63d42ecca 100644 --- a/numpy/ma/core.py +++ b/numpy/ma/core.py @@ -1936,6 +1936,10 @@ def masked_where(condition, a, copy=True): result = a.view(cls) # Assign to *.mask so that structured masks are handled correctly. result.mask = _shrink_mask(cond) + # There is no view of a boolean so when 'a' is a MaskedArray with nomask + # the update to the result's mask has no effect. + if not copy and hasattr(a, '_mask') and getmask(a) is nomask: + a._mask = result._mask.view() return result diff --git a/numpy/ma/tests/test_core.py b/numpy/ma/tests/test_core.py index 9bfb82d1f..b71fa9069 100644 --- a/numpy/ma/tests/test_core.py +++ b/numpy/ma/tests/test_core.py @@ -5175,6 +5175,16 @@ def test_masked_array(): a = np.ma.array([0, 1, 2, 3], mask=[0, 0, 1, 0]) assert_equal(np.argwhere(a), [[1], [3]]) +def test_masked_array_no_copy(): + # check nomask array is updated in place + a = np.ma.array([1, 2, 3, 4]) + _ = np.ma.masked_where(a == 3, a, copy=False) + assert_array_equal(a.mask, [False, False, True, False]) + # check masked array is updated in place + a = np.ma.array([1, 2, 3, 4], mask=[1, 0, 0, 0]) + _ = np.ma.masked_where(a == 3, a, copy=False) + assert_array_equal(a.mask, [True, False, True, False]) + def test_append_masked_array(): a = np.ma.masked_equal([1,2,3], value=2) b = np.ma.masked_equal([4,3,2], value=2) @@ -5213,7 +5223,6 @@ def test_append_masked_array_along_axis(): assert_array_equal(result.data, expected.data) assert_array_equal(result.mask, expected.mask) - def test_default_fill_value_complex(): # regression test for Python 3, where 'unicode' was not defined assert_(default_fill_value(1 + 1j) == 1.e20 + 0.0j) |