Re: Comments merging, pass 2

On Mon, 13 Dec 2004 09:27:22 -0500, Blake Winton <blake-dlUKtbW3TlBcVw/[email protected]> wrote:
> Various people wrote:
> > Logically, though, "return (a and [b] or [c])[0]" has to be one
> > dictionary allocation larger than
> >
> > if a: return b
> > else: return c
> 
> Not if the list is lazily evaluated (as it indeed is in Python).
> 
> Both cases evaluate a.  If a is false, then a and [b] has to be false,
> so [b] doesn't even get constructed, and it skips to the "or [c]".  On
> the other hand, if a is true, then "a and [b]" will be true, so [c]
> doesn't get evaluated, since true or anything is still true.
> 

I agree with you that a) Python is lazily evaluated and that b) one of
either [b] or [c] is not constructed. However, one of those two needs
to be constructed, and it isn't in the if/else example, right? So the
memory allocation should be one *list* larger (I meant list when I
said dictionary above) in the ternary-ish thing than in a normal
if-else statement.

Peace
Bill Mill


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