From: Raymond Hettinger <python@rcn.com>
Date: Mon, 29 Jun 2009 18:34:46 +0000 (+0000)
Subject: Issue 6370: Performance issue with collections.Counter().
X-Git-Tag: v3.1.1rc1~119
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=77b31ef202359e6f29d261b7dfbb356f36d49123;p=python

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

diff --git a/Lib/collections.py b/Lib/collections.py
index bd5d3e86f9..f255919f0f 100644
--- a/Lib/collections.py
+++ b/Lib/collections.py
@@ -421,13 +421,15 @@ class Counter(dict):
         if iterable is not None:
             if isinstance(iterable, Mapping):
                 if self:
+                    self_get = self.get
                     for elem, count in iterable.items():
-                        self[elem] += count
+                        self[elem] = count + self_get(elem, 0)
                 else:
                     dict.update(self, iterable) # fast path when counter is empty
             else:
+                self_get = self.get
                 for elem in iterable:
-                    self[elem] += 1
+                    self[elem] = 1 + self_get(elem, 0)
         if kwds:
             self.update(kwds)