any() and all() on empty list?

Carl Banks invalidemail at aerojockey.com
Fri Mar 31 19:29:53 CEST 2006


Ron Adam wrote:
> Carl Banks wrote:
>
> > In Python, yes and no are the only possible answers.  Probably the only
> > analogous thing you could do in Python would be for all() to raise
> > ValueError when passed an empty sequence.
>
> There is also 'None' which serves a similar purpose of indicating an
> invalid value when passing arguments.

If all() were to return None, then if would essentially be like
returning False, because an if-statement would treat False and None the
same (as would most anything else expecting a boolean value).

The only reasonable way to say "false assumption" in Python is to raise
an exception.


Carl Banks




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