On Tuesday 21 October 2003 03:41 pm, Nick Coghlan wrote: ---
What about:
result + x**2 from result = 0.0 for x in S
Essentially short for: result = 0.0 for x in S: result = result + x**2
Not bad, but I'm not sure I like the strict limitation to "A = A + f(x)" forms (possibly with some other operator in lieu of + etc, of course). Say I want to make a sets.Set out of the iterator, for example: result.union([ x**2 ]) from result = sets.Set() for x in theiter now that's deucedly _inefficient_, consarn it!, because it maps to a loop of: result = result.union([ x** ]) so I may be tempted to try, instead: real_result = sets.Set() real_result.union_update([ x**2 ]) from fake_result = None for x in theiter and hoping the N silly rebindings of fake_result to None cost me less than not having to materialize a list from theiter would cost if I did real_result = sets.Set([ x**2 for x in theiter ]) I don't think we should encourage that sort of thing with the "implicit assignment" in accumulation. So, if it's an accumulation syntax we're going for, I'd much rather find ways to express whether we want [a] no assignment at all (as e.g for union_update), [b] plain assignment, [c] augmented assignment such as += or whatever. Sorry, no good idea comes to my mind now, but I _do_ think we'd want all three possibilities... Alex