PEP 270, uniq method for list objects, Jason Petrone

pep-0270.txt

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+PEP: 270
+Title: uniq method for list objects
+Version: $Revision$
+Last-Modified: $Date$
+Author: jp@demonseed.net (Jason Petrone)
+Status: Draft
+Type: Standards Track
+Created: 21-Aug-2001
+Python-Version: 2.2
+Post-History:
+
+
+Abstract
+
+    This PEP proposes adding a method for removing duplicate elements to
+    the list object.
+
+
+Rationale
+
+    Removing duplicates from a list is a common task.  I think it is
+    useful and general enough to belong as a method in list objects.
+    It also has potential for faster execution when implemented in C,
+    especially if optimization using hashing or sorted cannot be used.
+
+    On comp.lang.python there are many, many, posts[1] asking about
+    the best way to do this task.  Its a little tricky to implement
+    optimally and it would be nice to save people the trouble of
+    figuring it out themselves.
+
+
+Considerations
+
+    Tim Peters suggests trying to use a hash table, then trying to
+    sort, and finally falling back on brute force[2].  Should uniq
+    maintain list order at the expense of speed?
+
+    Is it spelled 'uniq' or 'unique'? 
+
+
+Reference Implementation
+
+    I've written the brute force version.  Its about 20 lines of code
+    in listobject.c.  Adding support for hash table and sorted
+    duplicate removal would only take another hour or so.
+
+
+References
+
+    [1] http://groups.google.com/groups?as_q=duplicates&as_ugroup=comp.lang.python  
+
+    [2] Tim Peters unique() entry in the Python cookbook:
+        http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/52560/index_txt
+
+
+Copyright
+
+    This document has been placed in the public domain.
+
+
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