[Python-Dev] Adding any() and all()
Rodrigo Dias Arruda Senra
rodsenra at gpr.com.br
Fri Mar 11 15:58:47 CET 2005
[ Pierre Barbier de Reuille ]:
> They are called "sometrue" and "alltrue" ... IMHO, it explicits more
> what it means :
> alltrue(i<5 for i in l)
> sometrue(i<5 for i in l)
[ from a comment in GvR's blog ]
> > Why not,
> > if True in (x > 42 for x in S):
> > instead of "any" and why not
> > if not False in (x > 42 for x in S):
> > instead of "all"?
> Because "any" and "all" have shortcut semantics (they
> return as soon as they can determine the final result).
[ Guido ]:
> See my blog:
> Do we even need a PEP ?
In the absence of a PEP, soon will see in c.l.p discussions like:
For completeness sake shouldn't there be a optimiztion
version for nonetrue() ?
for x in S:
why not allfalse() ?
Due to the previous use of sometrue(), guess it becomes
easier to remeber nonetrue() than allfalse().
One may argue for aliasing(nonetrue, allfalse), and we are
back to _builtin pollution_.
So, people might fallback to any() and all(),realising that:
'''not all()''' meaning somefalse()
'''not any()''' meaning nonetrue()==allfalse()
All I'm saying: +1 for the PEP.
It is curious though that we choose to read an *implicit*
True in [all(), any()] instead of an implicit False.
I guess that is a moral or ethical choice coming from the Human
realm, favouring Truth instead of Falsity. But that difference
does not hold in the Boolean realm <wink>.
MSc Computer Engineer rodsenra at gpr.com.br
GPr Sistemas Ltda http://www.gpr.com.br
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