diff options
| -rw-r--r-- | Lib/collections/__init__.py | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/Lib/collections/__init__.py b/Lib/collections/__init__.py index 6794de1f8e..80dc4f6d4e 100644 --- a/Lib/collections/__init__.py +++ b/Lib/collections/__init__.py @@ -753,14 +753,22 @@ class Counter(dict): def __pos__(self): 'Adds an empty counter, effectively stripping negative and zero counts' - return self + Counter() + result = Counter() + for elem, count in self.items(): + if count > 0: + result[elem] = count + return result def __neg__(self): '''Subtracts from an empty counter. Strips positive and zero counts, and flips the sign on negative counts. ''' - return Counter() - self + result = Counter() + for elem, count in self.items(): + if count < 0: + result[elem] = 0 - count + return result def _keep_positive(self): '''Internal method to strip elements with a negative or zero count''' |