Python: hash() yields different results for different platforms

• dennis_lee_bieber / 200 / Fri, 27 Mar 2009 05:39:00 GMT / Comments (0)
• On 11 Jul 2006 16:33:50 -0700, "Qiangning Hong" <hongqn...gmail.com>
  declaimed the following in comp.lang.python:
  
  > I believe this will be faster than making the "url" column unique key
  > and doing string comparation. Right?
  >
  Given that the queries pass the data as strings, you're trading an
  integer->string, string->integer conversion pair on each search,
  followed by an index file look-up, for a straight index file look-up.
  
  Granted, my college days were a quarter century ago, but at the
  time, the data structures class required implementing a hash table
  look-up program (hashed-head, multiple-linked list). Hashes weren't
  guaranteed to be unique -- the hash only gave an entry point from which
  one then performed string comparisons. *
  
  You could maybe use MD5 encoding if you don't want the pure URL in
  the look-up, and MySQL, at least, has a built-in for MD5 so you wouldn't
  even have to worry about "differences".
  
  * The Amiga file-system was a hashed-head, multiple-linked list -- the
  only place I'd ever encountered one outside of that 3rd year college
  course. File-names were hashed into an index into a directory block; the
  directory block had pointers to file-header/subdirectory blocks... those
  blocks then had a linked list to other fh/sd blocks that shared the hash
  value.
  --
  Wulfraed Dennis Lee Bieber KD6MOG
  wlfraed...ix.netcom.com wulfraed...bestiaria.com
  HTTP://wlfraed.home.netcom.com/
  (Bestiaria Support Staff: web-asst...bestiaria.com)
  HTTP://www.bestiaria.com/
• Keywords:

  hash, yields, different, results, platforms, python

• http://programming.itags.org/python/32375/«« Last Thread - Next Thread »»