On 10/16/2011 9:17 PM, Ian Kelly wrote:
On Sun, Oct 16, 2011 at 5:52 PM, Ganesh Gopalakrishnan
<gan...@cs.utah.edu> wrote:
This probably is known, but a potential pitfall (was, for me) nevertheless.
I suspect it is due to hash collisions between 's3' and 's13' in this case?
It happens only rarely, depending on the contents of the set.
I'm not sure exactly which keys are colliding here, but in general the
iteration order of a set (or dict) depends not just on the contents,
but also on the order of insertion. And of course the repr depends on
the iteration order -- anything consistent would require sorting,
which would be O(n log n) and is not even necessarily well-defined.
To put it another way, any dependence on the arbitrary ordering of
unordered collections in iteration or displays is a programming error.
--
Terry Jan Reedy
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