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Issue 6370: Performance issue with collections.Counter().

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This commit is contained in:
Raymond Hettinger 2009-06-29 18:34:46 +00:00
parent 2c3de40971
commit 77b31ef202
1 changed files with 4 additions and 2 deletions
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6
Lib/collections.py
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@ -421,13 +421,15 @@ class Counter(dict):
if iterable is not None: if iterable is not None:
if isinstance(iterable, Mapping): if isinstance(iterable, Mapping):
if self: if self:
self_get = self.get
for elem, count in iterable.items(): for elem, count in iterable.items():
self[elem] += count self[elem] = count + self_get(elem, 0)
else: else:
dict.update(self, iterable) # fast path when counter is empty dict.update(self, iterable) # fast path when counter is empty
else: else:
self_get = self.get
for elem in iterable: for elem in iterable:
self[elem] += 1 self[elem] = 1 + self_get(elem, 0)
if kwds: if kwds:
self.update(kwds) self.update(kwds)