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


Groups > comp.lang.python > #5700

Re: English Idiom in Unix: Directory Recursively

Path csiph.com!x330-a1.tempe.blueboxinc.net!usenet.pasdenom.info!selfless.tophat.at!newsfeed.xs4all.nl!newsfeed6.news.xs4all.nl!xs4all!post.news.xs4all.nl!not-for-mail
Return-Path <ian.g.kelly@gmail.com>
X-Original-To python-list@python.org
Delivered-To python-list@mail.python.org
X-Spam-Status OK 0.024
X-Spam-Evidence '*H*': 0.95; '*S*': 0.00; 'wed,': 0.03; 'recursion': 0.09; 'url:%28': 0.09; 'url:%29': 0.09; 'am,': 0.14; 'wrote:': 0.14; '(lambda': 0.16; 'eg.': 0.16; 'recursive': 0.16; '\xa0do': 0.16; 'algorithm': 0.16; 'math': 0.16; 'cc:addr:python-list': 0.17; 'programming': 0.19; 'header:In-Reply-To:1': 0.21; 'cc:2**0': 0.22; 'cc:no real name:2**0': 0.23; 'received:209.85.161.46': 0.23; 'received:mail- fx0-f46.google.com': 0.23; 'url:wiki': 0.23; 'function': 0.25; 'expect': 0.25; 'definition': 0.26; 'not.': 0.26; 'received:209.85.161': 0.26; '(in': 0.26; 'thanks.': 0.27; "i'm": 0.27; 'message-id:@mail.gmail.com': 0.28; 'class': 0.29; 'cc:addr:python.org': 0.30; 'second': 0.30; 'differently': 0.30; 'throwing': 0.30; 'it.': 0.31; 'usage': 0.32; 'programming,': 0.32; "we're": 0.34; 'thus,': 0.35; 'using': 0.35; 'received:google.com': 0.37; 'useful': 0.37; 'received:209.85': 0.37; 'mathematical': 0.37; 'url:en': 0.37; 'url:org': 0.38; 'but': 0.38; 'implemented': 0.38; 'subject:: ': 0.38; '8bit%:6': 0.39; 'explain': 0.39; 'received:209': 0.39; 'more': 0.60; 'exact': 0.65; 'links,': 0.67; 'url:%1': 0.68; 'below:': 0.79; 'different.': 0.84; 'aka': 0.91; 'presumably': 0.91; 'subject:English': 0.91; 'technique': 0.93; 'roots': 0.95
DKIM-Signature v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc:content-type:content-transfer-encoding; bh=WDkzX62NAFzLb5X6emo0lX4soSW/oyhkkCJNBNlzt/E=; b=aFFwajSvvwIxkz4/F7EWUJGXvf1GrLKQW21uX3pqSNlVInk7rVFBpqLAfWZ/Umn3ah lHUku9010GrrvxcjZ0tEgVfcIjEPWL08EGnE88kU/dIMnzSAd4Qmzbcpth38Id8TfSPN JZImyuj7kerTw6X6Udv46YqxrS/hIJNRXUmC8=
DomainKey-Signature a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc:content-type:content-transfer-encoding; b=w6I/srjclW8L9rh3rsrWxn8Hv/w8Z8vs2Z8895UwOeZrGteYJ2wMtQYRDt6e4UUzSz oH6RBC2s7amTJDFCBXkwklVxGFbLLmODJOuivQsi/fTUmue5ZGIM/10ZKBSH+6P9H+uY 7nM0VWAtEHwDS9sfC//v9r8Cnq7I3GQX2t3mA=
MIME-Version 1.0
In-Reply-To <436ff55b-f61d-46a8-b5ea-f29d73190aba@s41g2000prb.googlegroups.com>
References <c159267e-22f9-4821-a70d-2f111cc35de4@f31g2000pri.googlegroups.com> <iqvj9f$3ci$6@dont-email.me> <2acf55f1-0415-4a13-8e16-aa3418d149c2@r35g2000prj.googlegroups.com> <mailman.1745.1305701913.9059.python-list@python.org> <436ff55b-f61d-46a8-b5ea-f29d73190aba@s41g2000prb.googlegroups.com>
From Ian Kelly <ian.g.kelly@gmail.com>
Date Wed, 18 May 2011 08:32:29 -0600
Subject Re: English Idiom in Unix: Directory Recursively
To rusi <rustompmody@gmail.com>
Content-Type text/plain; charset=ISO-8859-1
Content-Transfer-Encoding quoted-printable
Cc python-list@python.org
X-BeenThere python-list@python.org
X-Mailman-Version 2.1.12
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.1753.1305729181.9059.python-list@python.org> (permalink)
Lines 41
NNTP-Posting-Host 82.94.164.166
X-Trace 1305729181 news.xs4all.nl 49174 [::ffff:82.94.164.166]:34205
X-Complaints-To abuse@xs4all.nl
Xref x330-a1.tempe.blueboxinc.net comp.lang.python:5700

Show key headers only | View raw


On Wed, May 18, 2011 at 1:10 AM, rusi <rustompmody@gmail.com> wrote:
>> Um, it is.  Consider the simple function (lambda x, y: x + y).
>> Mathematically, this function is recursive.  Algorithmically, it is
>> not.  Do you disagree?
>
> See the definition of primitive recursion eg.
>
> http://en.wikipedia.org/wiki/Primitive_recursive_function#Definition
>
> (2 of the second set of "more complex" definitions) from where the
> name 'primitive recursion' is presumably derived)
>
> And for the more general (wider) class of 'recursive' functions (in
> the math sense aka computable functions) see a little below:
>
> http://en.wikipedia.org/wiki/Primitive_recursive_function#Relationship_to_recursive_functions

I know what primitive recursive and computable functions are, thanks.
What you're failing to explain is why you would consider that function
to be recursive from a programming standpoint.  In programming, when
we say a function is recursive, we mean that it is implemented using
the technique of recursion, not that it is computable.  Since we're
throwing around Wikipedia links, see the definition in the first
sentence at:

http://en.wikipedia.org/wiki/Recursion_%28computer_science%29

In fact, the mathematical definition would not be useful for
programming since to us a function is an implementation of an
algorithm (I expect Lispers may quibble over this, but it is true even
there).  Thus, in programming, all functions are computable.

> Of course I grant that the adjective 'recursive' is used differently
> in computability and in programming but the roots are not all that
> different.

Not just the adjective 'recursive', but also the noun 'function'.  I'm
not sure of the exact etymology of 'recursive', although I would bet
that the mathematical usage came first and the programming usage is a
derivative of it.

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


Thread

English Idiom in Unix: Directory Recursively Xah Lee <xahlee@gmail.com> - 2011-05-17 15:26 -0700
  Re: English Idiom in Unix: Directory Recursively Ian Kelly <ian.g.kelly@gmail.com> - 2011-05-17 17:20 -0600
    Re: English Idiom in Unix: Directory Recursively "Martin P. Hellwig" <martin.hellwig@gmail.com> - 2011-05-18 22:22 +0000
  Re: English Idiom in Unix: Directory Recursively Chris Angelico <rosuav@gmail.com> - 2011-05-18 09:42 +1000
  Re: English Idiom in Unix: Directory Recursively "Steven W. Orr" <steveo@syslang.net> - 2011-05-17 21:16 -0400
  Re: English Idiom in Unix: Directory Recursively Roland Hutchinson <my.spamtrap@verizon.net> - 2011-05-18 04:51 +0000
    Re: English Idiom in Unix: Directory Recursively "Pascal J. Bourguignon" <pjb@informatimago.com> - 2011-05-18 07:19 +0200
      Re: English Idiom in Unix: Directory Recursively tar@sevak.isi.edu (Thomas A. Russ) - 2011-05-17 23:42 -0700
        Re: English Idiom in Unix: Directory Recursively Hans Georg Schaathun <hg@schaathun.net> - 2011-05-18 09:26 +0100
          Re: English Idiom in Unix: Directory Recursively tar@sevak.isi.edu (Thomas A. Russ) - 2011-05-18 09:16 -0700
            Re: English Idiom in Unix: Directory Recursively Hans Georg Schaathun <hg@schaathun.net> - 2011-05-18 19:11 +0100
              Re: English Idiom in Unix: Directory Recursively Raymond Wiker <raw@RAWMBP-2.local> - 2011-05-18 20:20 +0200
                Re: English Idiom in Unix: Directory Recursively Hans Georg Schaathun <hg@schaathun.net> - 2011-05-18 19:39 +0100
                Re: English Idiom in Unix: Directory Recursively Raymond Wiker <raw@RAWMBP-2.local> - 2011-05-18 21:09 +0200
                Re: English Idiom in Unix: Directory Recursively Hans Georg Schaathun <hg@schaathun.net> - 2011-05-18 21:02 +0100
                Re: English Idiom in Unix: Directory Recursively Raymond Wiker <raw@RAWMBP-2.local> - 2011-05-18 22:40 +0200
                Re: English Idiom in Unix: Directory Recursively Hans Georg Schaathun <hg@schaathun.net> - 2011-05-19 05:56 +0100
                Re: English Idiom in Unix: Directory Recursively tar@sevak.isi.edu (Thomas A. Russ) - 2011-05-19 16:14 -0700
                Re: English Idiom in Unix: Directory Recursively Chris Angelico <rosuav@gmail.com> - 2011-05-19 04:41 +1000
            Re: English Idiom in Unix: Directory Recursively Chris Angelico <rosuav@gmail.com> - 2011-05-19 04:12 +1000
            Re: English Idiom in Unix: Directory Recursively "Pascal J. Bourguignon" <pjb@informatimago.com> - 2011-05-18 20:57 +0200
              Re: English Idiom in Unix: Directory Recursively tar@sevak.isi.edu (Thomas A. Russ) - 2011-05-19 16:17 -0700
                Re: English Idiom in Unix: Directory Recursively "Pascal J. Bourguignon" <pjb@informatimago.com> - 2011-05-20 02:38 +0200
                Re: English Idiom in Unix: Directory Recursively Antti J Ylikoski <antti.ylikoski@tkk.fi> - 2011-05-20 12:00 +0300
        Re: English Idiom in Unix: Directory Recursively Peter Moylan <invalid@peter.pmoylan.org.invalid> - 2011-05-18 22:09 +1000
          Re: English Idiom in Unix: Directory Recursively rusi <rustompmody@gmail.com> - 2011-05-18 06:14 -0700
            Re: English Idiom in Unix: Directory Recursively Peter Moylan <invalid@peter.pmoylan.org.invalid> - 2011-05-19 11:06 +1000
              Re: English Idiom in Unix: Directory Recursively Jonathan de Boyne Pollard <J.deBoynePollard-newsgroups@NTLWorld.COM> - 2011-05-21 09:32 +0100
                Re: English Idiom in Unix: Directory Recursively Lars Enderin <lars.enderin@telia.com> - 2011-05-21 11:52 +0200
                Re: English Idiom in Unix: Directory Recursively Lars Enderin <lars.enderin@telia.com> - 2011-05-21 11:54 +0200
                Re: English Idiom in Unix: Directory Recursively Lars Enderin <lars.enderin@telia.com> - 2011-05-21 11:56 +0200
              Re: English Idiom in Unix: Directory Recursively Grant Edwards <invalid@invalid.invalid> - 2011-05-21 15:34 +0000
      Re: English Idiom in Unix: Directory Recursively Roland Hutchinson <my.spamtrap@verizon.net> - 2011-05-20 06:50 +0000
    Re: English Idiom in Unix: Directory Recursively rusi <rustompmody@gmail.com> - 2011-05-17 23:06 -0700
      Re: English Idiom in Unix: Directory Recursively Harrison Hill <harrishill@gmx.com> - 2011-05-17 23:50 -0700
        Re: English Idiom in Unix: Directory Recursively rusi <rustompmody@gmail.com> - 2011-05-18 00:16 -0700
        Re: English Idiom in Unix: Directory Recursively Peter Moylan <invalid@peter.pmoylan.org.invalid> - 2011-05-18 22:19 +1000
          Re: English Idiom in Unix: Directory Recursively rantingrick <rantingrick@gmail.com> - 2011-05-29 13:16 -0700
            Re: English Idiom in Unix: Directory Recursively Peter Moylan <invalid@peter.pmoylan.org.invalid> - 2011-05-30 22:58 +1000
        Re: English Idiom in Unix: Directory Recursively see@sig.for.address (Victor Eijkhout) - 2011-05-18 12:59 -0500
          Re: English Idiom in Unix: Directory Recursively Roland Hutchinson <my.spamtrap@verizon.net> - 2011-05-20 06:54 +0000
            Re: English Idiom in Unix: Directory Recursively Chris Angelico <rosuav@gmail.com> - 2011-05-20 17:10 +1000
          Re: English Idiom in Unix: Directory Recursively rantingrick <rantingrick@gmail.com> - 2011-05-29 13:28 -0700
            Re: English Idiom in Unix: Directory Recursively Peter Moylan <invalid@peter.pmoylan.org.invalid> - 2011-05-30 23:02 +1000
          Re: English Idiom in Unix: Directory Recursively rantingrick <rantingrick@gmail.com> - 2011-05-29 13:28 -0700
        Re: English Idiom in Unix: Directory Recursively Glenn Knickerbocker <NotR@bestweb.net> - 2011-05-18 16:54 -0400
      Re: English Idiom in Unix: Directory Recursively Ian Kelly <ian.g.kelly@gmail.com> - 2011-05-18 00:58 -0600
        Re: English Idiom in Unix: Directory Recursively rusi <rustompmody@gmail.com> - 2011-05-18 00:10 -0700
          Re: English Idiom in Unix: Directory Recursively Ian Kelly <ian.g.kelly@gmail.com> - 2011-05-18 08:32 -0600
            Re: English Idiom in Unix: Directory Recursively rusi <rustompmody@gmail.com> - 2011-05-18 08:15 -0700
              Re: English Idiom in Unix: Directory Recursively Ian Kelly <ian.g.kelly@gmail.com> - 2011-05-18 09:43 -0600
  Re: English Idiom in Unix: Directory Recursively Hans Georg Schaathun <hg@schaathun.net> - 2011-05-18 09:12 +0100
    Re: English Idiom in Unix: Directory Recursively Espen Vestre <espen@vestre.net> - 2011-05-18 10:20 +0200
    Re: English Idiom in Unix: Directory Recursively Rikishi42 <skunkworks@rikishi42.net> - 2011-05-19 23:21 +0200
      Re: English Idiom in Unix: Directory Recursively Hans Georg Schaathun <hg@schaathun.net> - 2011-05-20 05:28 +0100
        Re: English Idiom in Unix: Directory Recursively Rikishi42 <skunkworks@rikishi42.net> - 2011-05-23 20:48 +0200
      Re: English Idiom in Unix: Directory Recursively rusi <rustompmody@gmail.com> - 2011-05-19 22:13 -0700
        Re: English Idiom in Unix: Directory Recursively Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-05-20 06:55 +0000
          Re: English Idiom in Unix: Directory Recursively Hans Georg Schaathun <hg@schaathun.net> - 2011-05-20 09:48 +0100
            Re: English Idiom in Unix: Directory Recursively rusi <rustompmody@gmail.com> - 2011-05-20 10:21 -0700
          Re: English Idiom in Unix: Directory Recursively Rikishi42 <skunkworks@rikishi42.net> - 2011-05-23 20:56 +0200
            Re: English Idiom in Unix: Directory Recursively Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-05-24 00:18 +0000
              Re: English Idiom in Unix: Directory Recursively Rikishi42 <skunkworks@rikishi42.net> - 2011-05-25 00:06 +0200
                Re: English Idiom in Unix: Directory Recursively Chris Angelico <rosuav@gmail.com> - 2011-05-25 10:40 +1000
                Re: English Idiom in Unix: Directory Recursively rantingrick <rantingrick@gmail.com> - 2011-05-29 14:18 -0700
                Re: English Idiom in Unix: Directory Recursively rantingrick <rantingrick@gmail.com> - 2011-05-29 14:19 -0700
                Re: English Idiom in Unix: Directory Recursively Xah Lee <xahlee@gmail.com> - 2011-05-24 23:05 -0700
                Re: English Idiom in Unix: Directory Recursively Thorsten Kampe <thorsten@thorstenkampe.de> - 2011-05-25 09:26 +0200
                Re: English Idiom in Unix: Directory Recursively Xah Lee <xahlee@gmail.com> - 2011-05-25 00:51 -0700
                Re: English Idiom in Unix: Directory Recursively Chris Angelico <rosuav@gmail.com> - 2011-05-25 17:59 +1000
                Re: English Idiom in Unix: Directory Recursively Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-05-25 21:59 +0000
                Re: English Idiom in Unix: Directory Recursively Thorsten Kampe <thorsten@thorstenkampe.de> - 2011-05-26 10:48 +0200
                Re: English Idiom in Unix: Directory Recursively Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-05-26 10:06 +0000
                Re: English Idiom in Unix: Directory Recursively Thorsten Kampe <thorsten@thorstenkampe.de> - 2011-05-26 12:46 +0200
                Re: English Idiom in Unix: Directory Recursively harrismh777 <harrismh777@charter.net> - 2011-05-27 09:31 -0500
                Re: English Idiom in Unix: Directory Recursively Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-05-25 22:58 +0000
                Re: English Idiom in Unix: Directory Recursively Chris Angelico <rosuav@gmail.com> - 2011-05-26 14:00 +1000
                Re: English Idiom in Unix: Directory Recursively Thorsten Kampe <thorsten@thorstenkampe.de> - 2011-05-26 10:59 +0200
                Re: English Idiom in Unix: Directory Recursively "Charles" <C.Sanders@DeleteThis.Bom.GOV.AU> - 2011-05-26 20:58 +1000
                Re: English Idiom in Unix: Directory Recursively Chris Angelico <rosuav@gmail.com> - 2011-05-26 21:12 +1000
                Re: English Idiom in Unix: Directory Recursively rantingrick <rantingrick@gmail.com> - 2011-05-29 14:38 -0700
                Re: English Idiom in Unix: Directory Recursively Chris Angelico <rosuav@gmail.com> - 2011-05-30 07:46 +1000
                Re: English Idiom in Unix: Directory Recursively rantingrick <rantingrick@gmail.com> - 2011-05-29 15:54 -0700
                Re: English Idiom in Unix: Directory Recursively rantingrick <rantingrick@gmail.com> - 2011-05-29 14:38 -0700
                Re: English Idiom in Unix: Directory Recursively Thorsten Kampe <thorsten@thorstenkampe.de> - 2011-05-26 13:20 +0200
                Re: English Idiom in Unix: Directory Recursively Chris Angelico <rosuav@gmail.com> - 2011-05-26 21:28 +1000
                Re: English Idiom in Unix: Directory Recursively Xah Lee <xahlee@gmail.com> - 2011-05-26 14:51 -0700
                Re: English Idiom in Unix: Directory Recursively Rikishi42 <skunkworks@rikishi42.net> - 2011-05-28 21:36 +0200
                Re: English Idiom in Unix: Directory Recursively Chris Angelico <rosuav@gmail.com> - 2011-05-29 05:58 +1000
                Re: English Idiom in Unix: Directory Recursively Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-05-29 00:49 +0000
                Re: English Idiom in Unix: Directory Recursively Rikishi42 <skunkworks@rikishi42.net> - 2011-05-30 23:04 +0200
                Re: English Idiom in Unix: Directory Recursively Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-05-30 23:17 +0000
                Re: English Idiom in Unix: Directory Recursively Chris Angelico <rosuav@gmail.com> - 2011-05-29 07:28 +1000
                Re: English Idiom in Unix: Directory Recursively Rikishi42 <skunkworks@rikishi42.net> - 2011-05-30 23:10 +0200
                Re: English Idiom in Unix: Directory Recursively rantingrick <rantingrick@gmail.com> - 2011-05-29 13:58 -0700
                Re: English Idiom in Unix: Directory Recursively Chris Angelico <rosuav@gmail.com> - 2011-05-30 07:27 +1000
          Re: English Idiom in Unix: Directory Recursively rantingrick <rantingrick@gmail.com> - 2011-05-29 13:39 -0700
  Re: English Idiom in Unix: Directory Recursively Mike Barnes <mikebarnes@bluebottle.com> - 2011-05-18 10:25 +0100
    Re: English Idiom in Unix: Directory Recursively Xah Lee <xahlee@gmail.com> - 2011-05-18 13:00 -0700
      Re: English Idiom in Unix: Directory Recursively Hans Georg Schaathun <hg@schaathun.net> - 2011-05-18 21:19 +0100
        Re: English Idiom in Unix: Directory Recursively Lanarcam <lanarcam1@yahoo.fr> - 2011-05-18 22:33 +0200
      Re: English Idiom in Unix: Directory Recursively Mike Barnes <mikebarnes@bluebottle.com> - 2011-05-18 22:00 +0100
      Re: English Idiom in Unix: Directory Recursively Jonathan de Boyne Pollard <J.deBoynePollard-newsgroups@NTLWorld.COM> - 2011-05-20 08:10 +0100
        Re: English Idiom in Unix: Directory Recursively Xah Lee <xahlee@gmail.com> - 2011-05-22 13:22 -0700
          Re: English Idiom in Unix: Directory Recursively Chris Angelico <rosuav@gmail.com> - 2011-05-23 08:46 +1000
            Re: English Idiom in Unix: Directory Recursively Xah Lee <xahlee@gmail.com> - 2011-05-22 16:17 -0700
              Re: English Idiom in Unix: Directory Recursively Chris Angelico <rosuav@gmail.com> - 2011-05-23 09:32 +1000
                Re: English Idiom in Unix: Directory Recursively Xah Lee <xahlee@gmail.com> - 2011-05-23 21:20 -0700
                Re: English Idiom in Unix: Directory Recursively Chris Angelico <rosuav@gmail.com> - 2011-05-24 14:28 +1000
                Re: English Idiom in Unix: Directory Recursively Xah Lee <xahlee@gmail.com> - 2011-05-24 10:40 -0700
                Re: English Idiom in Unix: Directory Recursively Chris Angelico <rosuav@gmail.com> - 2011-05-25 08:14 +1000
                Re: English Idiom in Unix: Directory Recursively Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-05-25 10:15 +0000
      Re: English Idiom in Unix: Directory Recursively rantingrick <rantingrick@gmail.com> - 2011-05-29 13:32 -0700
    Re: English Idiom in Unix: Directory Recursively Jonathan de Boyne Pollard <J.deBoynePollard-newsgroups@NTLWorld.COM> - 2011-05-20 08:07 +0100
  Re: English Idiom in Unix: Directory Recursively John Nagle <nagle@animats.com> - 2011-05-18 13:07 -0700
  Re: English Idiom in Unix: Directory Recursively Jonathan de Boyne Pollard <J.deBoynePollard-newsgroups@NTLWorld.COM> - 2011-05-20 08:00 +0100
    Re: English Idiom in Unix: Directory Recursively David Schwartz <davids@webmaster.com> - 2011-05-27 22:56 -0700

csiph-web