danieldelay wrote:
Le 09/06/2010 00:24, Ian Kelly a écrit :
Because it was designed as a replacement for "reduce(lambda x, y: x or
y, iterable)". The problem arises when the iterable is empty. What
false value should be returned? If the iterable is a sequence of
bools, then None doesn't fit. If the iterable is a sequence of
non-bool objects, then False doesn't fit. In the case of reduce, the
problem is solved by explicitly specifying an initial value to be used
when the sequence is empty, but I guess GVR didn't feel that was
appropriate here.
Cheers,
Ian
Thanks for your reply, it helps me to understand this choice wether I do
not agree with it.
"False" sounds natural for a function called "any()" which makes a
boolean calculus
"None" sounds natural for a function called "firsttrue()" which tries to
retrieve an element.
As the two make sense, I would have chosen the "firsttrue()" which is
more powerfull...
Perhaps "any()" whas choosen to keep a beautiful symmetry with "all()",
that I can interprete only as a boolean calculus.
Does GVR prefers beauty to power ?
firsttrue(line.strip() for line in '\n\n \n CHEERS \n'.split('\n'))
Should 'firsttrue' return None? Surely, if none are true then it should
raise an exception.
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