From 038ca2a5516f6b445a8548f3999d1db3b6b8abb1 Mon Sep 17 00:00:00 2001 From: Raymond Hettinger Date: Sat, 13 Aug 2005 02:29:58 +0000 Subject: Teach the sets module to correctly compute s-=s and s^=s as the empty set. --- Lib/sets.py | 4 ++++ Lib/test/test_sets.py | 13 +++++++++++++ 2 files changed, 17 insertions(+) diff --git a/Lib/sets.py b/Lib/sets.py index 8ec7e2f..32a0dd6 100644 --- a/Lib/sets.py +++ b/Lib/sets.py @@ -480,6 +480,8 @@ class Set(BaseSet): value = True if not isinstance(other, BaseSet): other = Set(other) + if self is other: + self.clear() for elt in other: if elt in data: del data[elt] @@ -497,6 +499,8 @@ class Set(BaseSet): data = self._data if not isinstance(other, BaseSet): other = Set(other) + if self is other: + self.clear() for elt in ifilter(data.has_key, other): del data[elt] diff --git a/Lib/test/test_sets.py b/Lib/test/test_sets.py index c5a48b1..ff834e0 100644 --- a/Lib/test/test_sets.py +++ b/Lib/test/test_sets.py @@ -243,6 +243,19 @@ class TestBinaryOps(unittest.TestCase): self.assertRaises(TypeError, cmp, a, 12) self.assertRaises(TypeError, cmp, "abc", a) + def test_inplace_on_self(self): + t = self.set.copy() + t |= t + self.assertEqual(t, self.set) + t &= t + self.assertEqual(t, self.set) + t -= t + self.assertEqual(len(t), 0) + t = self.set.copy() + t ^= t + self.assertEqual(len(t), 0) + + #============================================================================== class TestUpdateOps(unittest.TestCase): -- cgit v0.12