On Wed, Jan 27, 2010 at 11:30 PM, Steve Howell <showel...@yahoo.com> wrote:
>
>
> --- On Wed, 1/27/10, Raymond Hettinger <raymond.hettin...@gmail.com> wrote:
>
>> From: Raymond Hettinger <raymond.hettin...@gmail.com>
>
>> * the current design encourages people to use
>> the right data structure for a given need.  the
>> proposed change makes the trades-off murky and
>> implementation dependent.
>
> Are you saying that the current slowness of list for prepops helps people to 
> choose more appropriate data structures?  Really????
>
>> you have to know a lot more
>> in order to make the right choices.  that's not
>> good for usability.  we want tools that are easy to use
>> correctly/well.
>
> If you want tools that are easy to use correctly, make them bug-free and 
> document their behavior.  If you want tools that are easy to use well, then 
> make them perform better.  I am not sure how my patch contradicts either of 
> these goals.
>
> You keep making the argument that deque is a better alternative to list in 
> many situations.  I actually agree with you.  Most programming problems are 
> best modelled by a queue.  I am not sure why Python lists get all the syntax 
> sugar and promotion over deque, when in reality, Python lists implement a 
> pretty useless data structure.  Python lists are a glorification of a C array 
> built on top of a memory-upward-biased memory allocator.  As such, they 
> optimize list appends (good) but fail awfully on list prepops (bad).  They 
> are much better as stacks than queues, even though queues are more useful for 
> the most common programming known to man--work through a work queue and 
> delete tasks when they are done.
>
> It is not surprising that Python lists are starting to show their lack of 
> versatility in 2010.  They're based on 1970's technology.  Python lists are 
> really just a thin encapsulation of C arrays built on top of an asymmetrical 
> memory manager.
>
> In 2010 you could improve Python lists by releasing from the constraints of 
> 1970s semantics.  But I am starting to think a more modern approach would be 
> to take more useful data structures like deques and give them more sugar.
>
>
>
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"Python lists implement a pretty useless data structure"

It's very difficult for ideas to gain traction when they contain such
useless, and obviously wrong, rhetoric.  There's an enormous body of
code out there that begs to disagree with this assertion.

Alex

-- 
"I disapprove of what you say, but I will defend to the death your
right to say it." -- Voltaire
"The people's good is the highest law." -- Cicero
"Code can always be simpler than you think, but never as simple as you
want" -- Me
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