Perl-Python-a-Day: Sorting

[Marcin 'Qrczak' Kowalczyk]

Re: Perl-Python-a-Day: Sorting

Abdulaziz Ghuloum <aghuloum@c-s-remove-dashes.indiana. edu> writes:
[color=blue]
> Python FAQs contain an entry to the schwartzian transform.
>
> http://www.python.org/doc/faq/progra...form-in-python[/color]

This entry is obsolete: it should mention the 'key' option of the
standard sort method.

--
__("< Marcin Kowalczyk
\__/ qrczak@knm.org. pl
^^ http://qrnik.knm.org.pl/~qrczak/

[Tim Roberts]

Re: Perl-Python-a-Day: Sorting

Marcin 'Qrczak' Kowalczyk <qrczak@knm.org .pl> wrote:
[color=blue]
>Abdulaziz Ghuloum <aghuloum@c-s-remove-dashes.indiana. edu> writes:
>[color=green]
>> Python FAQs contain an entry to the schwartzian transform.
>>
>> http://www.python.org/doc/faq/progra...form-in-python[/color]
>
>This entry is obsolete: it should mention the 'key' option of the
>standard sort method.[/color]

It should mention it, but not necessarily recommend it.

I haven't run the numbers in Python, but in Perl, the undecorated sort is
so well-optimized that the Schwartzian transform is almost always faster
than passing a custom comparator to the sort function.
--
- Tim Roberts, timr@probo.com
Providenza & Boekelheide, Inc.

[Fredrik Lundh]

Re: Perl-Python-a-Day: Sorting

Tim Roberts wrote:
[color=blue][color=green]
> >This entry is obsolete: it should mention the 'key' option of the
> >standard sort method.[/color]
>
> It should mention it, but not necessarily recommend it.
>
> I haven't run the numbers in Python, but in Perl, the undecorated sort is
> so well-optimized that the Schwartzian transform is almost always faster
> than passing a custom comparator to the sort function.[/color]

the "key" option is used for decoration. from the documentation:

key specifies a function of one argument that is used to extract
a comparison key from each list element: "key=str.lo wer"

In general, the key and reverse conversion processes are
much faster than specifying an equivalent cmp function. This
is because cmp is called multiple times for each list element
while key and reverse touch each element only once.

</F>

[Xah Lee]

Re: bizarro world (was Re: Python Doc Problem Example: sort() (reprise))


Bryan wrote:[color=blue]
> mr. xah... would you be willing to give a lecture at pycon 2006? i'm sure you
> would draw a huge crowd and a lot of people would like to meet you in person...
>
> thanks.[/color]

I'd be delight to.

My requirements are: 1 cup of fat-free milk, free, and free pizza.

Xah
xah@xahlee.org
∑ http://xahlee.org/

[Terry Hancock]

Re: bizarro world (was Re: Python Doc Problem Example: sort()(reprise) )

print """\
On Monday 17 October 2005 02:59 am, Xah Lee wrote:[color=blue]
>
> Bryan wrote:[color=green]
> > mr. xah... would you be willing to give a lecture at pycon 2006? i'm sure you
> > would draw a huge crowd and a lot of people would like to meet you in person...
> >
> > thanks.[/color]
>
> I'd be delight to.
>
> My requirements are: 1 cup of fat-free milk, free, and free pizza.[/color]
""".replace('cr owd', 'angry mob')

;-D
--
Terry Hancock ( hancock at anansispacework s.com )
Anansi Spaceworks http://www.anansispaceworks.com

[Lucas Raab]

Re: Perl-Python-a-Day: Sorting

[snip]
[color=blue]
> Thanks. I didn't know there's also a sort function in Python (2.4),
> besides the method. (i've mentioned your name as acknowledgement at my
> website essay)[/color]

[snip]

With his permission, of course...

--
--------------------------
Lucas Raab
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