Bengt Richter wrote:
> Perhaps newbies should be advised that
>
> [x for x in l1 if x in set(l2)]
But the resulting list is a representative of bag not a set ( contains
multiple occurrences of elements ):
>>> [x for x in [3, 3] if s in Set([3])]
[3,3]
Same with Raymonds solution:
>>> filt
On 2/12/06, Felipe Almeida Lessa <[EMAIL PROTECTED]> wrote:
> Em Dom, 2006-02-12 às 23:15 -0500, Steve Holden escreveu:
> > Given that Python 2.4 doesn't even perform simple constant folding for
> > arithmetic expressions
> > [snip]
>
> May I ask why doesn't it perform such optimization? Is there a
Felipe Almeida Lessa wrote:
> Em Dom, 2006-02-12 às 23:51 -0500, Steve Holden escreveu:
>
>>The basic answer is that so far no developer has felt it worthwhile to
>>expend time on adding these optimizations.
>
>
> I always thought these small optimizations could lead Python to be
> faster overa
Delaney, Timothy (Tim) wrote:
> Adding such optimisations to Python may improve it's benchmark scores,
Blegh! Time to give myself a good kicking!
Tim Delaney
--
http://mail.python.org/mailman/listinfo/python-list
Em Dom, 2006-02-12 às 23:51 -0500, Steve Holden escreveu:
> The basic answer is that so far no developer has felt it worthwhile to
> expend time on adding these optimizations.
I always thought these small optimizations could lead Python to be
faster overall. I remember about this every time I see
Steve Holden wrote:
> The basic answer is that so far no developer has felt it worthwhile to
> expend time on adding these optimizations.
Mainly because it's rare to find such constructs in anything except
contrived examples ... Nearly every time you use a literal, it's being
added to (subtracted
Felipe Almeida Lessa wrote:
> Em Dom, 2006-02-12 às 23:15 -0500, Steve Holden escreveu:
>
>>Given that Python 2.4 doesn't even perform simple constant folding for
>>arithmetic expressions
>>[snip]
>
>
> May I ask why doesn't it perform such optimization? Is there any special
> difficulties in d
Em Dom, 2006-02-12 às 23:15 -0500, Steve Holden escreveu:
> Given that Python 2.4 doesn't even perform simple constant folding for
> arithmetic expressions
> [snip]
May I ask why doesn't it perform such optimization? Is there any special
difficulties in doing so with the Python compiler?
Also, I
Alex Martelli wrote:
> Bengt Richter <[EMAIL PROTECTED]> wrote:
>...
>
>>>Personally, I'd always use (depending on guesses regarding lengths of
>>>lists) [x for x in l1 if x in l2] or the setified equivalent, of course.
>>>
>>
>>Perhaps newbies should be advised that
>>
>>[x for x in l1 if
Bengt Richter <[EMAIL PROTECTED]> wrote:
...
> >Personally, I'd always use (depending on guesses regarding lengths of
> >lists) [x for x in l1 if x in l2] or the setified equivalent, of course.
> >
> Perhaps newbies should be advised that
>
> [x for x in l1 if x in set(l2)]
>
> is not a (w
On Sat, 11 Feb 2006 10:24:04 -0800, [EMAIL PROTECTED] (Alex Martelli) wrote:
>Raymond Hettinger <[EMAIL PROTECTED]> wrote:
> ...
>> The intersection step is unnecessary, so the answer can be simplified a
>> bit:
>>
>> >>> filter(set(l2).__contains__, l1)
>> [5, 3]
>> >>> filter(set(l1).__contai
Raymond Hettinger <[EMAIL PROTECTED]> wrote:
...
> The intersection step is unnecessary, so the answer can be simplified a
> bit:
>
> >>> filter(set(l2).__contains__, l1)
> [5, 3]
> >>> filter(set(l1).__contains__, l2)
> [3, 5]
...and if one has time to waste, "setification" being only an
opti
Raymond Hettinger wrote:
> The intersection step is unnecessary, so the answer can be simplified a
> bit:
>
> >>> filter(set(l2).__contains__, l1)
> [5, 3]
> >>> filter(set(l1).__contains__, l2)
> [3, 5]
stand corrected.
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http://mail.python.org/mailman/listinfo/python-list
[Amit Khemka]
> > Hello, Is there a *direct* way of doing set operations on lists which
> > preserve the order of the input lists ?
> > For Ex. l1 = [1, 5, 3, 2, 4, 7]
> > l2 = [3, 5, 10]
> >
> > and (l1 intersect l2) returns [5, 3] (and (l2 intersect l1)
[bonono]
> what d
Amit Khemka wrote:
> Hello, Is there a *direct* way of doing set operations on lists which
> preserve the order of the input lists ?
Nope
> For Ex. l1 = [1, 5, 3, 2, 4, 7]
> l2 = [3, 5, 10]
>
> and (l1 intersect l2) returns [5, 3] (and (l2 intersect l1)
> returns [3, 5])
Amit Khemka wrote:
> Hello, Is there a *direct* way of doing set operations on lists which
> preserve the order of the input lists ?
> For Ex. l1 = [1, 5, 3, 2, 4, 7]
> l2 = [3, 5, 10]
>
> and (l1 intersect l2) returns [5, 3] (and (l2 intersect l1)
> returns [3, 5])
>
what
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