http://code.activestate.com/recipes/users/178123/views/2013-03-06T05:38:15-08:00ActiveState Code Recipes2012-12-19T07:12:32-08:00Raymond Hettingerhttp://code.activestate.com/recipes/users/178123/http://code.activestate.com/recipes/576694-orderedset/

<p style="color: grey"> Python recipe 576694 by <a href="/recipes/users/178123/">Raymond Hettinger</a> (<a href="/recipes/tags/ordered/">ordered</a>, <a href="/recipes/tags/set/">set</a>). Revision 9. </p> <p>Set that remembers original insertion order.</p>

2011-06-01T19:19:37-07:00Raymond Hettingerhttp://code.activestate.com/recipes/users/178123/http://code.activestate.com/recipes/577721-how-to-use-super-effectively-python-27-version/

<p style="color: grey"> Python recipe 577721 by <a href="/recipes/users/178123/">Raymond Hettinger</a> (<a href="/recipes/tags/cooperative/">cooperative</a>, <a href="/recipes/tags/inheritance/">inheritance</a>, <a href="/recipes/tags/multiple/">multiple</a>, <a href="/recipes/tags/next_in_mro/">next_in_mro</a>, <a href="/recipes/tags/super/">super</a>). Revision 8. </p> <p>Python's super() provides a unique and amazing capability. It allows subclasses to be written to reorder a chain method calls. The recipe demonstrates all of the tradecraft needed to get super() to do your bidding.</p>

2011-04-24T03:20:45-07:00Raymond Hettingerhttp://code.activestate.com/recipes/users/178123/http://code.activestate.com/recipes/576693-ordered-dictionary-for-py24/

<p style="color: grey"> Python recipe 576693 by <a href="/recipes/users/178123/">Raymond Hettinger</a> (<a href="/recipes/tags/dictionary/">dictionary</a>, <a href="/recipes/tags/linked_list/">linked_list</a>, <a href="/recipes/tags/ordered/">ordered</a>). Revision 9. </p> <p>Drop-in substitute for Py2.7's new collections.OrderedDict. The recipe has big-oh performance that matches regular dictionaries (amortized O(1) insertion/deletion/lookup and O(n) iteration/repr/copy/equality_testing).</p>

2002-10-27T15:35:32-08:00Raymond Hettingerhttp://code.activestate.com/recipes/users/178123/http://code.activestate.com/recipes/159462-how-to-set-environment-variables/

<p style="color: grey"> Python recipe 159462 by <a href="/recipes/users/178123/">Raymond Hettinger</a> (<a href="/recipes/tags/sysadmin/">sysadmin</a>). </p> <p>Writes environment variables using a batch file wrapper. Overcomes an operating system limitation.</p>

2009-05-26T22:44:39-07:00Raymond Hettingerhttp://code.activestate.com/recipes/users/178123/http://code.activestate.com/recipes/500261-named-tuples/

<p style="color: grey"> Python recipe 500261 by <a href="/recipes/users/178123/">Raymond Hettinger</a> (<a href="/recipes/tags/shortcuts/">shortcuts</a>). Revision 15. </p> <p>Fast, lightweight attribute-style access to tuples.</p>

2012-11-23T23:57:31-08:00Raymond Hettingerhttp://code.activestate.com/recipes/users/178123/http://code.activestate.com/recipes/577504-compute-memory-footprint-of-an-object-and-its-cont/

<p style="color: grey"> Python recipe 577504 by <a href="/recipes/users/178123/">Raymond Hettinger</a> (<a href="/recipes/tags/memory/">memory</a>, <a href="/recipes/tags/sizeof/">sizeof</a>). Revision 3. </p> <p>Recursive version sys.getsizeof(). Extendable with custom handlers.</p>

2010-09-01T02:12:33-07:00Raymond Hettingerhttp://code.activestate.com/recipes/users/178123/http://code.activestate.com/recipes/577197-sortedcollection/

<p style="color: grey"> Python recipe 577197 by <a href="/recipes/users/178123/">Raymond Hettinger</a> (<a href="/recipes/tags/bisect/">bisect</a>, <a href="/recipes/tags/collection/">collection</a>, <a href="/recipes/tags/sorted/">sorted</a>). Revision 9. </p> <p>Wraps bisect.bisect() in an easy to use class that supports key-functions and straight-forward search methods.</p>

2009-03-28T23:32:08-07:00Raymond Hettingerhttp://code.activestate.com/recipes/users/178123/http://code.activestate.com/recipes/393090-binary-floating-point-summation-accurate-to-full-p/

<p style="color: grey"> Python recipe 393090 by <a href="/recipes/users/178123/">Raymond Hettinger</a> (<a href="/recipes/tags/algorithms/">algorithms</a>). Revision 5. </p> <p>Completely eliminates rounding errors and loss of significance due to catastrophic cancellation during summation. Achieves exactness by keeping full precision intermediate subtotals. Offers three alternative approaches, each using a different technique to store exact subtotals.</p>

2009-04-29T07:28:14-07:00Raymond Hettingerhttp://code.activestate.com/recipes/users/178123/http://code.activestate.com/recipes/362715-dbf-reader-and-writer/

<p style="color: grey"> Python recipe 362715 by <a href="/recipes/users/178123/">Raymond Hettinger</a> (<a href="/recipes/tags/database/">database</a>). Revision 7. </p> <p>Reader iterates over records in Dbase or Xbase files. Writer creates dbf files from Python sequences.</p>

2004-12-03T09:13:43-08:00Raymond Hettingerhttp://code.activestate.com/recipes/users/178123/http://code.activestate.com/recipes/355045-spreadsheet/

<p style="color: grey"> Python recipe 355045 by <a href="/recipes/users/178123/">Raymond Hettinger</a> (<a href="/recipes/tags/programs/">programs</a>). Revision 2. </p> <p>Use eval() to drive spreadsheet style logic. The sleeper feature of Py2.4 is the ability to use any object with a mapping interface as the locals argument to eval().</p>

2011-10-22T18:40:32-07:00Raymond Hettingerhttp://code.activestate.com/recipes/users/178123/http://code.activestate.com/recipes/577916-fast-minmax-function/

<p style="color: grey"> Python recipe 577916 by <a href="/recipes/users/178123/">Raymond Hettinger</a> (<a href="/recipes/tags/minmax/">minmax</a>, <a href="/recipes/tags/sorting/">sorting</a>). </p> <p>Minimizes the number of comparisons to compute the minimum and maximum of a dataset. Uses 1.5 compares for every element, improving on the more obvious solution that does 2 comparisons per element.</p>

2009-06-29T12:24:14-07:00Raymond Hettingerhttp://code.activestate.com/recipes/users/178123/http://code.activestate.com/recipes/576611-counter-class/

<p style="color: grey"> Python recipe 576611 by <a href="/recipes/users/178123/">Raymond Hettinger</a> . Revision 11. </p> <p>Bag/multiset class for convenient tallying of hashable objects.</p>

2010-11-16T08:36:38-08:00Raymond Hettingerhttp://code.activestate.com/recipes/users/178123/http://code.activestate.com/recipes/277940-decorator-for-bindingconstants-at-compile-time/

<p style="color: grey"> Python recipe 277940 by <a href="/recipes/users/178123/">Raymond Hettinger</a> (<a href="/recipes/tags/programs/">programs</a>). Revision 9. </p> <p>Decorator for automatic code optimization. If a global is known at compile time, replace it with a constant. Fold tuples of constants into a single constant. Fold constant attribute lookups into a single constant.</p>

2010-08-01T01:19:23-07:00Raymond Hettingerhttp://code.activestate.com/recipes/users/178123/http://code.activestate.com/recipes/498245-lru-and-lfu-cache-decorators/

<p style="color: grey"> Python recipe 498245 by <a href="/recipes/users/178123/">Raymond Hettinger</a> (<a href="/recipes/tags/shortcuts/">shortcuts</a>). Revision 6. </p> <p>One-line decorator call adds caching to functions with hashable arguments and no keyword arguments. When the maximum size is reached, the least recently used entry or least frequently used entry is discarded -- appropriate for long-running processes which cannot allow caches to grow without bound. Includes built-in performance instrumentation.</p>

2011-09-06T20:01:46-07:00Raymond Hettingerhttp://code.activestate.com/recipes/users/178123/http://code.activestate.com/recipes/576642-persistent-dict-with-multiple-standard-file-format/

<p style="color: grey"> Python recipe 576642 by <a href="/recipes/users/178123/">Raymond Hettinger</a> (<a href="/recipes/tags/dbm/">dbm</a>, <a href="/recipes/tags/dictionary/">dictionary</a>, <a href="/recipes/tags/persistent/">persistent</a>, <a href="/recipes/tags/shelve/">shelve</a>). Revision 10. </p> <p>dbdict: a dbm based on a dict subclass.</p> <p>On open, loads full file into memory. On close, writes full dict to disk (atomically). Supported output file formats: csv, json, and pickle. Input file format automatically discovered.</p> <p>Usable by the shelve module for fast access.</p>

2010-02-07T14:40:03-08:00Raymond Hettingerhttp://code.activestate.com/recipes/users/178123/http://code.activestate.com/recipes/576930-efficient-running-median-using-an-indexable-skipli/

<p style="color: grey"> Python recipe 576930 by <a href="/recipes/users/178123/">Raymond Hettinger</a> (<a href="/recipes/tags/advanced_data_structure/">advanced_data_structure</a>, <a href="/recipes/tags/container/">container</a>, <a href="/recipes/tags/median/">median</a>, <a href="/recipes/tags/new_algorithm/">new_algorithm</a>, <a href="/recipes/tags/skiplist/">skiplist</a>, <a href="/recipes/tags/sliding_window/">sliding_window</a>). Revision 10. </p> <p>Maintains sorted data as new elements are added and old one removed as a sliding window advances over a stream of data. Also gives fast indexed access to value. Running time per median update is proportional to the log of the window size.</p>

2010-04-04T23:28:40-07:00Raymond Hettingerhttp://code.activestate.com/recipes/users/178123/http://code.activestate.com/recipes/576653-convert-a-cmp-function-to-a-key-function/

<p style="color: grey"> Python recipe 576653 by <a href="/recipes/users/178123/">Raymond Hettinger</a> (<a href="/recipes/tags/2_to_3/">2_to_3</a>). Revision 5. </p> <p>Py3.0 transition aid. The <em>sorted()</em> builtin and the <em>list.sort()</em> method no longer accept a <em>cmp</em> function in Python 3.0. Most cases are easy to convert manually. This recipe handles the remaining cases.</p>

2004-11-30T07:57:31-08:00Raymond Hettingerhttp://code.activestate.com/recipes/users/178123/http://code.activestate.com/recipes/259174-bag-collection-class/

<p style="color: grey"> Python recipe 259174 by <a href="/recipes/users/178123/">Raymond Hettinger</a> (<a href="/recipes/tags/algorithms/">algorithms</a>). Revision 6. </p> <p>Implement Smalltalk's bag class (similar to MultiSets in C++ or bag's in Objective C or Haskell's Edison module).</p>

2013-03-06T05:38:15-08:00Raymond Hettingerhttp://code.activestate.com/recipes/users/178123/http://code.activestate.com/recipes/578078-py26-and-py30-backport-of-python-33s-lru-cache/

<p style="color: grey"> Python recipe 578078 by <a href="/recipes/users/178123/">Raymond Hettinger</a> (<a href="/recipes/tags/cache/">cache</a>, <a href="/recipes/tags/lru/">lru</a>). Revision 6. </p> <p>Full-featured O(1) LRU cache backported from Python3.3. The full Py3.3 API is supported (thread safety, maxsize, keyword args, type checking, __wrapped__, and cache_info). Includes Py3.3 optimizations for better memory utilization, fewer dependencies, and fewer dict lookups.</p>

2011-06-04T17:44:21-07:00Raymond Hettingerhttp://code.activestate.com/recipes/users/178123/http://code.activestate.com/recipes/577684-bloom-filter/

<p style="color: grey"> Python recipe 577684 by <a href="/recipes/users/178123/">Raymond Hettinger</a> (<a href="/recipes/tags/big_table/">big_table</a>, <a href="/recipes/tags/bloom_filter/">bloom_filter</a>, <a href="/recipes/tags/sets/">sets</a>, <a href="/recipes/tags/spelling_checker/">spelling_checker</a>, <a href="/recipes/tags/spell_checker/">spell_checker</a>). Revision 18. </p> <p>Space efficient, probabilistic set membership tester. Has no False Negatives but allows a rare False Positive.</p>