+1 to what Nick said. And I thought about this carefully when designing the language. It's not a bug. The note about assignment RHS being evaluated before LHS is normative -- you just have to interpret RHS as "after the *last* '=' symbol". Assignment itself is *not* an expression.
On Tue, Nov 6, 2012 at 4:01 AM, Nick Coghlan <ncogh...@gmail.com> wrote: > As noted, it's really only counterintuitive if your intuition is primed to > expect C style right to left chained assignments. > > Python, on the other hand, is able to preserve primarily left to right > evaluation in this case with only the far right hand expression needing to > be evaluated out of order. > > One example that can really make the intended behaviour clear: > > *a = *b = iter(range(3)) > > a ends up as (0,1,2), b ends up as (), because the first assignment consumes > the entire iterable. > > My actual advice, though? If the order of assignment really matters, use > multiple assignment statements rather than relying on readers knowing the > assignment order. > > Cheers, > Nick. > > -- > Sent from my phone, thus the relative brevity :) > > > _______________________________________________ > Python-Dev mailing list > Python-Dev@python.org > http://mail.python.org/mailman/listinfo/python-dev > Unsubscribe: > http://mail.python.org/mailman/options/python-dev/guido%40python.org > -- --Guido van Rossum (python.org/~guido) _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
