[Python-ideas] for/else syntax

[Jim Jewett]

On Thu, Oct 1, 2009 at 1:17 AM, Stephen J. Turnbull <stephen at xemacs.org> wrote:
> Note: As a native speaker, since "for ... else" isn't English, I would
> certainly look up the semantics before using the syntax.  This is very
> probably true for Japanese as well, who are far better at (consciously)
> remembering English syntax than native speakers are.  I don't know
> about other non-natives.

As another native speaker, I do find it confusing on most for loops --
so I don't use it there.  It does make sense on search loops.

Normal loop, where it is misleading:

    for item in source:
        process(item)
    else:
        # yikes, I would wrongly expect this to mean empty.


But search loop where it makes sense:

    for candidate in source:
        if test(candidate):
            choice=candidate
            break
    else:
        choice=default

(That said, even then, I tend to set the default outside the loop
construct, just to avoid the else confusion.)

-jJ