Python never guaranteed an order

Posted Apr 12, 2012 4:21 UTC (Thu) by theophrastus (guest, #80847)
In reply to: Python never guaranteed an order by david.a.wheeler
Parent article: Python 2.6.8, 2.7.3, 3.1.5, and 3.2.3 security release

I had no idea that there was any order there. So what order does it have? Just the same for each "for k in dict.keys():" or what? (i don't think it's alphabetical ...[checking]... nope)

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Python never guaranteed an order

Posted Apr 12, 2012 8:41 UTC (Thu) by job (guest, #670) [Link] (3 responses)

It's just that the order is deterministic, it does not necessarily make any sense to a human observer. It all depends on how the internal hash function works.

Python never guaranteed an order

Posted Apr 12, 2012 17:11 UTC (Thu) by theophrastus (guest, #80847) [Link] (2 responses)

Oh... ok, thank you for that.

(must resist asking what isn't "deterministic" inside most computers if one has enough knowledge of their current state... must.... resist...)

Python never guaranteed an order

Posted Apr 12, 2012 19:13 UTC (Thu) by man_ls (guest, #15091) [Link]

I believe instead of "deterministic" you could use "consistent" or "always the same": the order doesn't change with time and is the same from one run to the next. Not everything inside a computer can be said to behave this way: for instance processes which change with absolute time, with durations or with user or device input. Or processes that have been made to depend on the above factors intentionally to avoid predictable behavior (as in the original security hole).

Python never guaranteed an order

Posted Apr 13, 2012 11:39 UTC (Fri) by dskoll (subscriber, #1630) [Link]

In theory, /dev/random is non-deterministic because it uses sources of entropy whose internal state is (for practical purposes) impossible to know well enough to make any predictions.