On Mon, 19 Sep 2005 22:31:05 +0000, Bengt Richter wrote:
> On Mon, 19 Sep 2005 23:46:05 +1000, Steven D'Aprano <[EMAIL PROTECTED]> wrote:
>>Are there actually any usage cases for *needing* a Boolean value? Any
>>object can be used for truth testing, eg:
[snip]
> making an index (it's an int subclass), as in
>
> >>> things = None, 0, 1, 0.0, 5.0, '', 'a', [], [1], {}, {1:2}
> >>> for thing in things:
> ... print 'if %-6r would act like if %s' % (thing,
> ('False','True')[bool(thing)])
> ...
That's a pretty artificial example though. Your general index ranges from
0 to n inclusive, where n is unlikely to be 1. That limits the usefulness
of the idiom sequence_or_mapping[bool(thing)] to a tiny set of cases.
As near as I can tell, explicitly converting objects to booleans is mostly
useful for demonstrating that booleans aren't needed for truth testing.
--
Steven.
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