diff options
| -rw-r--r-- | numpy/ma/core.py | 15 | ||||
| -rw-r--r-- | numpy/ma/tests/test_core.py | 15 |
2 files changed, 30 insertions, 0 deletions
diff --git a/numpy/ma/core.py b/numpy/ma/core.py index e24cb956c..5c446252b 100644 --- a/numpy/ma/core.py +++ b/numpy/ma/core.py @@ -6385,6 +6385,21 @@ class MaskedConstant(MaskedArray): # it's a subclass, or something is wrong, make it obvious return object.__repr__(self) + def __format__(self, format_spec): + # Replace ndarray.__format__ with the default, which supports no format characters. + # Supporting format characters is unwise here, because we do not know what type + # the user was expecting - better to not guess. + try: + return object.__format__(self, format_spec) + except TypeError: + # 2020-03-23, NumPy 1.19.0 + warnings.warn( + "Format strings passed to MaskedConstant are ignored, but in future may " + "error or produce different behavior", + FutureWarning, stacklevel=2 + ) + return object.__format__(self, "") + def __reduce__(self): """Override of MaskedArray's __reduce__. """ diff --git a/numpy/ma/tests/test_core.py b/numpy/ma/tests/test_core.py index 3bfb42555..98fc7dd97 100644 --- a/numpy/ma/tests/test_core.py +++ b/numpy/ma/tests/test_core.py @@ -447,6 +447,21 @@ class TestMaskedArray: assert_equal(copied.mask, [0, 0, 0]) assert_equal(a.mask, [0, 1, 0]) + def test_format(self): + a = array([0, 1, 2], mask=[False, True, False]) + assert_equal(format(a), "[0 -- 2]") + assert_equal(format(masked), "--") + assert_equal(format(masked, ""), "--") + + # Postponed from PR #15410, perhaps address in the future. + # assert_equal(format(masked, " >5"), " --") + # assert_equal(format(masked, " <5"), "-- ") + + # Expect a FutureWarning for using format_spec with MaskedElement + with assert_warns(FutureWarning): + with_format_string = format(masked, " >5") + assert_equal(with_format_string, "--") + def test_str_repr(self): a = array([0, 1, 2], mask=[False, True, False]) assert_equal(str(a), '[0 -- 2]') |