[Python-Dev] Issue 2986: difflib.SequenceMatcher is partly broken (original) (raw)

Antoine Pitrou solipsis at pitrou.net
Wed Jul 7 13:08:48 CEST 2010

On Tue, 06 Jul 2010 19🔞09 -0400 Terry Reedy <tjreedy at udel.edu> wrote:

Version A: Modify the heuristic to only eliminate common items when there are more than, say, 100 items (when len(b2j)> 100 where b2j is first calculated without popularity deletions). [...] Version B: add a parameter to .init to make the heuristic optional. [...] Version C: A more radical alternative would be to make one or more of the tuning parameters user settable, with one setting turning it off.

Version B would have my favour (but please make the default be True). Version A can lead to regressions (including performance regressions such as described by Tim), and version C looks far more complicated to use.

Regards

Antoine.

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