Path: csiph.com!v102.xanadu-bbs.net!xanadu-bbs.net!feeder.erje.net!eu.feeder.erje.net!newsfeed.fsmpi.rwth-aachen.de!newsfeed.kamp.net!newsfeed.kamp.net!newsfeed.freenet.ag!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; 'that?': 0.05; '*not*': 0.07; 'binary': 0.07; 'subject:PEP': 0.07; 'string': 0.09; 'arguments': 0.09; 'converted': 0.09; 'formatting': 0.09; 'function,': 0.09; 'pretend': 0.09; 'received:80.91': 0.09; 'received:80.91.229': 0.09; 'received:gmane.org': 0.09; 'received:list': 0.09; 'def': 0.12; 'argument,': 0.16; 'formatted': 0.16; 'itself,': 0.16; 'operation.': 0.16; 'operator.': 0.16; 'received:80.91.229.3': 0.16; 'received:plane.gmane.org': 0.16; 'tuple': 0.16; 'tuple.': 0.16; 'typeerror:': 0.16; "why's": 0.16; 'wrote:': 0.18; '>>>': 0.22; 'hack': 0.22; 'header:User-Agent:1': 0.23; '(by': 0.24; 'header:X -Complaints-To:1': 0.27; 'header:In-Reply-To:1': 0.27; 'am,': 0.29; "doesn't": 0.30; '"",': 0.31; 'file': 0.32; 'another': 0.32; '(most': 0.33; 'problem': 0.35; 'represent': 0.38; 'handle': 0.38; 'needed': 0.38; 'to:addr:python-list': 0.38; 'pm,': 0.38; 'rather': 0.38; 'recent': 0.39; 'to:addr:python.org': 0.39; 'received:org': 0.40; 'dave': 0.60; 'received:173': 0.61; 'first': 0.61; 'making': 0.63; 'design.': 0.68; 'honest': 0.78; "'2'": 0.84; 'received:fios.verizon.net': 0.84; 'angel': 0.91; 'carlos': 0.91
X-Injected-Via-Gmane: http://gmane.org/
To: python-list@python.org
From: Terry Jan Reedy <tjreedy@udel.edu>
Subject: Re: PEP 378: Format Specifier for Thousands Separator
Date: Thu, 23 May 2013 16:19:33 -0400
References: <BLU176-W10190CB892A0414C988A05D7A80@phx.gbl>, , <nad-F52CE7.22440720052013@news.gmane.org>, , <CADUW+M=Y7b=4ZEENVzx4p6YpVD8T0eG=qz7sz8+iEow-5-o+jQ@mail.gmail.com>, , <BLU176-W9FF52BDCE42DAF40E6AC7D7A80@phx.gbl>, , <CANc-5UyWuCd+roRt5V5aocx0vEc1TXfDnG2-phy_gAKSRaqOBA@mail.gmail.com>, , <knghok$3bd$1@ger.gmane.org>, , <mailman.1936.1369166040.3114.python-list@python.org>, , <519c348a$0$6599$c3e8da3$5496439d@news.astraweb.com>, , <519C3D99.5040107@gmail.com>, , <mailman.1958.1369219519.3114.python-list@python.org>, , <519cdcff$0$6599$c3e8da3$5496439d@news.astraweb.com>, , <mailman.1972.1369249307.3114.python-list@python.org>, , <87eaaf24-df6a-4f6b-b873-16ca96c12e24@b2g2000yqe.googlegroups.com>, <mailman.1977.1369261949.3114.python-list@python.org>, <b8623121-631a-4464-bd23-0e210018de78@e13g2000yqp.googlegroups.com> <BLU176-W35FCA0F6068A230026ED88D7AA0@phx.gbl> <519E6327.8070204@davea.name>
Mime-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-1; 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/20130509 Thunderbird/17.0.6
In-Reply-To: <519E6327.8070204@davea.name>
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.2035.1369341281.3114.python-list@python.org>
Lines: 28
NNTP-Posting-Host: 2001:888:2000:d::a6
X-Trace: 1369341281 news.xs4all.nl 15892 [2001:888:2000:d::a6]:34361
X-Complaints-To: abuse@xs4all.nl
Xref: csiph.com comp.lang.python:45841

On 5/23/2013 2:42 PM, Dave Angel wrote:
> On 05/23/2013 11:26 AM, Carlos Nepomuceno wrote:

>
>>>>>> eggs(a,f)
>>> Traceback (most recent call last):
>>> File "<pyshell#29>", line 1, in <module>
>>> eggs(a,f)
>>> File "<pyshell#1>", line 1, in eggs
>>> def eggs(spam, ham): return spam % ham
>>> TypeError: not all arguments converted during string formatting
>>>>>> '%s'%(5%3)
>>> '2'
>>
>> So % doesn't handle tuples! Why's that? Is it intentional (by design)?
>>
>
> It's a conflict in the design.  A tuple is used to supply multiple
> arguments to the % operator.  So if you want to have a tuple as the
> first argument, you need to enclose it in another tuple.

The problem is that interpolating 1 to many items into a string is *not* 
a binary operation. The needed hack to pretend that it is, using a tuple 
to represent multiple items rather than just itself, was one of the 
reasons for making string formatting a honest function, where multiple 
items to be formatted are passed as multiple arguments.