[Python-checkins] r79481 - python/trunk/Doc/library/itertools.rst

[raymond.hettinger]

Author: raymond.hettinger
Date: Sun Mar 28 20:08:15 2010
New Revision: 79481

Log:
Add a note on optimizing the itertools recipes for production.

Modified:
   python/trunk/Doc/library/itertools.rst

Modified: python/trunk/Doc/library/itertools.rst
==============================================================================
--- python/trunk/Doc/library/itertools.rst	(original)
+++ python/trunk/Doc/library/itertools.rst	Sun Mar 28 20:08:15 2010
@@ -784,3 +784,9 @@
        except exception:
            pass
 
+Note, many of the above recipes can be optimized by replacing global lookups
+with local variables defined as default values.  For example, the
+*dotproduct* recipe can be written as::
+
+   def dotproduct(vec1, vec2, sum=sum, imap=imap, mul=operator.mul):
+       return sum(imap(mul, vec1, vec2))