On 8/28/21 6:23 AM, Marc-Andre Lemburg wrote:
To me, the behavior looked a lot like stripping NANs left and right from the list, but what you're explaining makes this appear even more as a bug in the implementation of median() - basically wrong assumptions about NANs sorting correctly. The outcome could be more or less random, it seems.
It isn't a 'bug in median()' making the wrong assumption about NANs sorting, it is an error in GIVING median a NAN which violates its precondition that the input have a total-order by the less than operator. Asking for the median value of a list that doesn't have a proper total order is a nonsense question, so you get a nonsense answer. It costs too much to have median test if the input does have a total order, just to try to report this sort of condition, that it won't be done for a general purpose operation. -- Richard Damon