On Tue, 24 Nov 2015 02:25 pm, George Trojan wrote: > The following code has bitten me recently: > > >>> t=(0,1) > >>> x,y=t if t else 8, 9 > >>> print(x, y) > (0, 1) 9 > > I was assuming that a comma has the highest order of evaluation, that is > the expression 8, 9 should make a tuple. Why this is not the case?
I'm not sure what sort of answer you are looking for. Why does anything have the precedence it has? Making assumptions about the comma's precedence in that way seems unsafe to me. Consider that function(a, b, c, d) is a function call with four arguments, NOT a single 4-tuple argument. And: py> 1, 2, 3 * 2 # expecting (1, 2, 3, 1, 2, 3) (1, 2, 6) So there's plenty of evidence that the comma has a very low order of evaluation, not the highest, and it seems remarkably unsafe to assume the opposite. Fortunately, it is very simple to test these things out at the interactive interpreter. I cannot imagine doing any Python programming without having a Python shell open and ready for me to try out code snippets. -- Steven -- https://mail.python.org/mailman/listinfo/python-list
