Paul Rubin wrote: > Boris Borcic <[EMAIL PROTECTED]> writes: >> x.sort(cmp = lambda x,y : cmp(random.random(),0.5)) >> pick a random shuffle of x with uniform distribution ? > > You really can't assume anything like that. Sorting assumes an order > relation on the items being sorted, which means if a < b and b < c, > then a < c. If your comparison operation doesn't preserve that > property then the sort algorithm could do anything, including looping > forever or crashing.
Not if it does the minimum number of comparisons to achieve the sort, in which case it won't ever call cmp() if the result is pre-determined by the order relation and previous comparisons, so that it will never get from this comparison function a system of answers that's not consistent with an order relation. That's obvious at least in the case where random.random() == 0.5 never occurs (and at first sight even the latter case shouldn't change it). Best, BB -- "On naît tous les mètres du même monde" -- http://mail.python.org/mailman/listinfo/python-list
