Yeah, they never emailed me the scores either, and told me there was no way to know at the booth... I even joked with them that they were just trying to link it

Yeah, they never emailed me the scores either, and told me there was no way to know at the booth... I even joked with them that they were just trying to link it to my fb profile. I actually didn't catch the trick until I asked someone later if they had gotten the same problem twice, "Almost, but the values were different" which is when I realized it (I blame the beer during opening night). However, as I found out today, because the way they worded the question it was all on a single line (if I remember correctly). So both cases should actually have been True, and I was right both times :P > (e.g. does pypy do the same? ironpython?) I wasted... ahem, spent a few hours today playing with this and found a few things, it's pretty neat! In PyPy, `is` will always be True for primitives. This also means NaN is NaN (but still never == NaN). It doesn't use memory location for things like id() like CPython does, but it guarantees you get a unique representation. [0] In CPython (3.5.2), it will always cache [-5, 256]. Here's the code that creates that array at startup [1] and each possible init/copy function calls this first to see if it's a cached int [2]. But it can sometimes cache other values! It also depends on if you do it from a module or the repl, and it's different depending on what scope or line each name/value is on. This one weirded out some coworkers, all from one continuous repl session: >>> x = 500 >>> x is 500 False >>> x = 500; x is 500 True >>> def wat(): ... x = 500 ... return x is 500 >>> wat() True >>> x = 500 >>> def wat_wat(): ... return x is 500 >>> wat_wat() False If you run it from a script you instead get True, True, True, False. You can disassemble it to get a hint at why. One uses STORE_FAST and LOAD_FAST, and the other LOAD_GLOBAL. >>> disassemble(wat.__code__) 2 0 LOAD_CONST 1 (500) 3 STORE_FAST 0 (x) 3 6 LOAD_FAST 0 (x) 9 LOAD_CONST 1 (500) 12 COMPARE_OP 8 (is) 15 RETURN_VALUE >>> disassemble(wat_wat.__code__) 2 0 LOAD_GLOBAL 0 (x) 3 LOAD_CONST 1 (500) 6 COMPARE_OP 8 (is) 9 RETURN_VALUE Now I'm still trying to figure out why STORE_FAST and LOAD_FAST cause it to use the same object, and why those only get called when it's interpreted together. When I figure this out I might put together a longer post about all this. Also don't use `is` for comparing integers. ;) [0] http://doc.pypy.org/en/latest/cpython_differences.html#object-identity-of-primitive-values-is-and-id http://doc.pypy.org/en/latest/cpython_differences.html#objec... [1] https://github.com/python/cpython/blob/master/Objects/longobject.c#L5491 https://github.com/python/cpython/blob/master/Objects/longob... [2] https://github.com/python/cpython/blob/ba85d69a3e3610bdd05f0dd372cf4ebca178c7fb/Objects/longobject.c#L63 https://github.com/python/cpython/blob/ba85d69a3e3610bdd05f0...