When is List Comprehension inappropriate?

Paddy paddy3118 at googlemail.com
Thu Mar 22 06:21:17 CET 2007


On Mar 22, 4:56 am, a... at mac.com (Alex Martelli) wrote:
> Paddy <paddy3... at googlemail.com> wrote:
>
>    ...
>
> > I have found that I have gone too far when I used listcomps for their
> > sideeffects rather than wanting the list produced, for example the
>
> I agree.
>
> > second listcomp below is an expression as statement I don't want the
> > list produced - just the effect on data.
>
> > >>> # some random ranges
> > >>> data = [range(random.randrange(3,7)) for x in range(4)]
> > >>> # but I want each range jumbled
> > >>> [ random.shuffle(d) for d in data]
> > [None, None, None, None]
> > >>> data
> > [[2, 0, 3, 1], [0, 2, 1], [3, 4, 1, 0, 2], [2, 1, 0, 3]]
>
> > (I do know how to re-write it).
>
> for d in data: random.shuffle(d)
>
> Alex

Hah,
"You just couldn't let it lie" ;-)

I just knew someone would bite, and re-write it.
Now to reel, you in. Its fish for dinner today!


- Paddy.




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