[Python-Dev] Re: comprehension abbreviation (was: Adding any() and all())

[Steve Holden]

Jim Jewett wrote:
> Gareth McCaughan wrote:
> 
>>Some bit of my brain is convinced that [x in stuff if condition]
>>is the Right Syntax and keeps making me type it even though
>>I know it doesn't work.
> 
> 
> (and I agree with Gareth)
> 
> 
> On Monday 2005-03-14 12:42, Eric Nieuwland wrote:
> 
>>The full syntax is:
>>[ f(x) for x in seq if pred(x) ]
>>being allowed to write 'x' instead of 'identity(x)' is already a 
>>shortcut, just as dropping the conditional part.
> 
> 
> I think this is the heart of the disagreement.
> 
> Mentally, I'm not collecting some function of x (which happens
> to be identity).  I am filtering an existing set.  Being able to
> collect f(x) instead is just a useful but hackish shortcut.
> 
Have it your own way, but if you happen to need a list of transformed 
elements of a filtered list (and that isn't an uncommon requirement) 
then the idea of selecting the set members and then transforming the 
copies as a separate step seems a little ... unnecessary.

Having to write

     [x for x in seq]

to produce a copy of a list doesn't seem that outrageous to me, and I 
don't find the predicate-less case of your proposal that convincing:

     [x in seq]

seems somehow too terse.

[...]

regards
  Steve
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