On Wednesday, July 16, 2014 11:41:49 AM UTC-7, Nils Bruin wrote: > That's because "and" and "or" are program flow constructs in python, as > they are in C (they have "shortcut evaluation" behaviour. They are > equivalent to > > (x<2) if bool(x<2) else (x<1) > > and > > (x<2) if not(bool(x<2)) else (x<1) > > except that the "x<2" doesn't get evaluated twice. >
My apologies: this should be the other way around. If (x<2) is false then there is no need to evaluate (x<1) to determine the result of "and" and hence the first value is returned. So the logic is "bool(x<2) == False" and hence "(x<2) and (x<1)" does not depend on the truth value of "(x<1)". Python has specified that the value of the first argument gets returned, rather than "False" explicitly, because that is the most versatile (albeit in this case confusing) behaviour. -- You received this message because you are subscribed to the Google Groups "sage-support" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-support+unsubscr...@googlegroups.com. To post to this group, send email to sage-support@googlegroups.com. Visit this group at http://groups.google.com/group/sage-support. For more options, visit https://groups.google.com/d/optout.
