Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.lang.python > #38560

Re: LangWart: Method congestion from mutate multiplicty

Path csiph.com!usenet.pasdenom.info!weretis.net!feeder1.news.weretis.net!feeder.erje.net!eu.feeder.erje.net!xlned.com!feeder3.xlned.com!news2.euro.net!newsgate.cistron.nl!newsgate.news.xs4all.nl!post.news.xs4all.nl!not-for-mail
Return-Path <python-python-list@m.gmane.org>
X-Original-To python-list@python.org
Delivered-To python-list@mail.python.org
X-Spam-Status OK 0.000
X-Spam-Evidence '*H*': 1.00; '*S*': 0.00; 'essentially': 0.04; 'method.': 0.05; 'builtin': 0.07; 'reason,': 0.07; 'try:': 0.07; '-1,': 0.09; 'received:80.91': 0.09; 'received:80.91.229': 0.09; 'received:gmane.org': 0.09; 'received:list': 0.09; 'terry': 0.09; 'def': 0.10; 'thread': 0.11; '-1):': 0.16; 'agree.': 0.16; 'expression.': 0.16; 'iterator,': 0.16; 'received:80.91.229.3': 0.16; 'received:plane.gmane.org': 0.16; 'reedy': 0.16; 'substituted': 0.16; 'surprising': 0.16; 'yield': 0.17; 'jan': 0.18; 'equivalent': 0.20; 'raise': 0.24; 'header:In-Reply-To:1': 0.25; 'header:User-Agent:1': 0.26; 'looks': 0.26; 'common': 0.26; 'header:X-Complaints-To:1': 0.28; 'trouble': 0.28; 'skip:_ 10': 0.29; 'returned': 0.30; 'getting': 0.33; 'to:addr:python-list': 0.33; 'list': 0.35; 'received:org': 0.36; 'except': 0.36; 'enough': 0.36; 'subject:: ': 0.38; 'to:addr:python.org': 0.39; 'list,': 0.39; 'short': 0.39; 'header:Received:5': 0.40; 'think': 0.40; 'range': 0.60; 'more': 0.63; 'premise': 0.84; 'received:fios.verizon.net': 0.84; 'tem': 0.84; 'worth,': 0.84
X-Injected-Via-Gmane http://gmane.org/
To python-list@python.org
From Terry Reedy <tjreedy@udel.edu>
Subject Re: LangWart: Method congestion from mutate multiplicty
Date Sun, 10 Feb 2013 03:39:21 -0500
References <680e50a4-6569-49cf-b369-0be450545d50@googlegroups.com> <5115c455$0$6574$c3e8da3$5496439d@news.astraweb.com> <d405822d-2252-4a85-8ab2-38ca88963d91@googlegroups.com>
Mime-Version 1.0
Content-Type text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding 7bit
X-Gmane-NNTP-Posting-Host pool-173-75-251-66.phlapa.fios.verizon.net
User-Agent Mozilla/5.0 (Windows NT 6.1; WOW64; rv:17.0) Gecko/20130107 Thunderbird/17.0.2
In-Reply-To <d405822d-2252-4a85-8ab2-38ca88963d91@googlegroups.com>
X-BeenThere python-list@python.org
X-Mailman-Version 2.1.15
Precedence list
List-Id General discussion list for the Python programming language <python-list.python.org>
List-Unsubscribe <http://mail.python.org/mailman/options/python-list>, <mailto:python-list-request@python.org?subject=unsubscribe>
List-Archive <http://mail.python.org/pipermail/python-list/>
List-Post <mailto:python-list@python.org>
List-Help <mailto:python-list-request@python.org?subject=help>
List-Subscribe <http://mail.python.org/mailman/listinfo/python-list>, <mailto:python-list-request@python.org?subject=subscribe>
Newsgroups comp.lang.python
Message-ID <mailman.1577.1360485575.2939.python-list@python.org> (permalink)
Lines 39
NNTP-Posting-Host 2001:888:2000:d::a6
X-Trace 1360485575 news.xs4all.nl 6851 [2001:888:2000:d::a6]:56541
X-Complaints-To abuse@xs4all.nl
Xref csiph.com comp.lang.python:38560

Show key headers only | View raw

While it is true that sorted(iterable) is essentially

def sorted(iterable):
   tem = list(iterable)
   tem.sort
   return tem

the body is not an expression and cannot be substituted in an 
expression. The need for the short form was thought common enough to be 
worth, *on balance*, a new builtin name. It is not surprising that not 
all agree.

Reversed(iterable) is more complicated because it returns an iterator, 
not a list, and looks for a class-specific __reversed__ method. I think 
it is more or less equivalent to the following:

def _rev_iter(seq, n):
   for i in range(n-1, -1, -1):
   # many people have trouble getting the range right
     yield seq[i]

def reversed(iterable):
   try:
     return iterable.__reversed__()
   except AttributeError:
     try:
       itlen = iterable.__len__
       iterable.__getitem__
       return _rev_iter(iterable, itlen)
     except AttributeError:
       raise TypeError("argument to reversed() must be a sequence")

Even if list mutation methods returned the list, which they do not and 
for good reason, reversed(it) is not the same as list(it).reverse(). So 
that part of the premise of this thread is wrong.

-- 
Terry Jan Reedy

Back to comp.lang.python | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

LangWart: Method congestion from mutate multiplicty Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-08 17:50 -0800
  Re: LangWart: Method congestion from mutate multiplicty Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-02-09 14:36 +1100
    Re: LangWart: Method congestion from mutate multiplicty Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-09 19:54 -0800
      Re: LangWart: Method congestion from mutate multiplicty Chris Angelico <rosuav@gmail.com> - 2013-02-10 15:20 +1100
      Re: LangWart: Method congestion from mutate multiplicty Mark Janssen <dreamingforward@gmail.com> - 2013-02-09 20:53 -0800
        Re: LangWart: Method congestion from mutate multiplicty Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-02-11 01:29 +1100
          Re: LangWart: Method congestion from mutate multiplicty Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2013-02-10 14:03 -0500
            Re: LangWart: Method congestion from mutate multiplicty Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-02-11 11:11 +1100
          Re: LangWart: Method congestion from mutate multiplicty Mark Janssen <dreamingforward@gmail.com> - 2013-02-10 13:28 -0800
            Re: LangWart: Method congestion from mutate multiplicty Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-02-11 11:10 +1100
              Re: LangWart: Method congestion from mutate multiplicty Mark Janssen <dreamingforward@gmail.com> - 2013-02-10 17:14 -0800
          Re: LangWart: Method congestion from mutate multiplicty Chris Angelico <rosuav@gmail.com> - 2013-02-11 08:51 +1100
          Re: LangWart: Method congestion from mutate multiplicty Mark Janssen <dreamingforward@gmail.com> - 2013-02-10 14:01 -0800
      Re: LangWart: Method congestion from mutate multiplicty Terry Reedy <tjreedy@udel.edu> - 2013-02-10 03:39 -0500
        Re: LangWart: Method congestion from mutate multiplicty Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-10 10:45 -0800
          Re: LangWart: Method congestion from mutate multiplicty Terry Reedy <tjreedy@udel.edu> - 2013-02-10 16:44 -0500
          Re: LangWart: Method congestion from mutate multiplicty Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-02-11 11:11 +1100
        Re: LangWart: Method congestion from mutate multiplicty Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-10 10:45 -0800
      Re: LangWart: Method congestion from mutate multiplicty Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-02-10 22:29 +1100
        Re: LangWart: Method congestion from mutate multiplicty Chris Angelico <rosuav@gmail.com> - 2013-02-11 00:24 +1100
          Re: LangWart: Method congestion from mutate multiplicty Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-02-11 01:00 +1100
        Re: LangWart: Method congestion from mutate multiplicty Tim Chase <python.list@tim.thechases.com> - 2013-02-10 07:52 -0600
        Re: LangWart: Method congestion from mutate multiplicty Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-10 15:59 -0800
          Re: LangWart: Method congestion from mutate multiplicty Tim Chase <python.list@tim.thechases.com> - 2013-02-10 18:12 -0600
            Re: LangWart: Method congestion from mutate multiplicty Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-10 17:24 -0800
            Re: LangWart: Method congestion from mutate multiplicty Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-10 17:24 -0800
          Re: LangWart: Method congestion from mutate multiplicty Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-02-11 11:36 +1100
            Re: LangWart: Method congestion from mutate multiplicty MRAB <python@mrabarnett.plus.com> - 2013-02-11 02:03 +0000
            Re: LangWart: Method congestion from mutate multiplicty Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-11 04:53 -0800
              Re: LangWart: Method congestion from mutate multiplicty Chris Angelico <rosuav@gmail.com> - 2013-02-12 00:27 +1100
                Re: LangWart: Method congestion from mutate multiplicty Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-11 20:55 -0800
                Re: LangWart: Method congestion from mutate multiplicty Mark Janssen <dreamingforward@gmail.com> - 2013-02-11 21:28 -0800
                Re: LangWart: Method congestion from mutate multiplicty Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-12 12:46 -0800
                Re: LangWart: Method congestion from mutate multiplicty Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-12 12:46 -0800
                Re: LangWart: Method congestion from mutate multiplicty Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-11 20:55 -0800
          Re: LangWart: Method congestion from mutate multiplicty alex23 <wuwei23@gmail.com> - 2013-02-10 18:05 -0800
            Re: LangWart: Method congestion from mutate multiplicty Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-02-11 07:19 +0000
            Re: LangWart: Method congestion from mutate multiplicty Chris Angelico <rosuav@gmail.com> - 2013-02-11 18:24 +1100
            Re: LangWart: Method congestion from mutate multiplicty Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-02-11 07:35 +0000
            Re: LangWart: Method congestion from mutate multiplicty Tim Chase <tim@thechases.com> - 2013-02-11 06:04 -0600
            Re: LangWart: Method congestion from mutate multiplicty Serhiy Storchaka <storchaka@gmail.com> - 2013-02-11 19:07 +0200
      Re: LangWart: Method congestion from mutate multiplicty Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2013-02-10 13:30 +0000
        Re: LangWart: Method congestion from mutate multiplicty Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-10 16:25 -0800
          Re: LangWart: Method congestion from mutate multiplicty Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-02-11 11:42 +1100
        Re: LangWart: Method congestion from mutate multiplicty Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-10 16:25 -0800
      Re: LangWart: Method congestion from mutate multiplicty Mark Janssen <dreamingforward@gmail.com> - 2013-02-10 10:45 -0800
    Re: LangWart: Method congestion from mutate multiplicty 88888 Dihedral <dihedral88888@googlemail.com> - 2013-02-10 06:33 -0800
  Re: LangWart: Method congestion from mutate multiplicty Chris Angelico <rosuav@gmail.com> - 2013-02-09 15:51 +1100
    Re: LangWart: Method congestion from mutate multiplicty alex23 <wuwei23@gmail.com> - 2013-02-10 17:56 -0800
      Re: LangWart: Method congestion from mutate multiplicty Chris Angelico <rosuav@gmail.com> - 2013-02-12 19:06 +1100
  Re: LangWart: Method congestion from mutate multiplicty Neil Hodgson <nhodgson@iinet.net.au> - 2013-02-10 20:53 +1100
    Re: LangWart: Method congestion from mutate multiplicty Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-02-10 22:30 +1100
    Re: LangWart: Method congestion from mutate multiplicty Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-10 10:55 -0800
      Re: LangWart: Method congestion from mutate multiplicty Neil Hodgson <nhodgson@iinet.net.au> - 2013-02-11 08:57 +1100

csiph-web