Fix minor subclassing issue with collections.Counter

This commit is contained in:
Raymond Hettinger 2011-04-15 13:12:21 -07:00
parent 65c620d0c7
commit 37c0fe56b9
3 changed files with 13 additions and 2 deletions

View File

@ -516,8 +516,8 @@ class Counter(dict):
self.subtract(kwds)
def copy(self):
'Like dict.copy() but returns a Counter instance instead of a dict.'
return Counter(self)
'Return a shallow copy.'
return self.__class__(self)
def __reduce__(self):
return self.__class__, (dict(self),)

View File

@ -689,6 +689,15 @@ class TestCounter(unittest.TestCase):
self.assertEqual(len(dup), len(words))
self.assertEqual(type(dup), type(words))
def test_copy_subclass(self):
class MyCounter(Counter):
pass
c = MyCounter('slartibartfast')
d = c.copy()
self.assertEqual(d, c)
self.assertEqual(len(d), len(c))
self.assertEqual(type(d), type(c))
def test_conversions(self):
# Convert to: set, list, dict
s = 'she sells sea shells by the sea shore'

View File

@ -58,6 +58,8 @@ Library
- Issue #11467: Fix urlparse behavior when handling urls which contains scheme
specific part only digits. Patch by Santoso Wijaya.
- collections.Counter().copy() now works correctly for subclasses.
- Issue #11474: Fix the bug with url2pathname() handling of '/C|/' on Windows.
Patch by Santoso Wijaya.