[ x for x in xrange(10) when p(x) ]

Alex Martelli aleax at mail.comcast.net
Thu Nov 10 04:53:21 CET 2005

bonono at gmail.com <bonono at gmail.com> wrote:

> Alex Martelli wrote:
> > This becomes a valid list comprehension by writing 'if' instead of
> > 'when'.
> valid, yes. efficient, I am not sure.
> [ x for x in xrange(10000000) if p(x) ]
> means I need to go through the whole range even if p = lambda x: x < 2.

Of course, barring semantically-very-deep optimizations (ones no
production implementation I know of ANY language would even try).  And,
your POINT would be...?


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