Path: csiph.com!usenet.pasdenom.info!weretis.net!feeder1.news.weretis.net!feeder.erje.net!eu.feeder.erje.net!newsfeed.xs4all.nl!newsfeed5.news.xs4all.nl!xs4all!newsgate.cistron.nl!newsgate.news.xs4all.nl!post.news.xs4all.nl!not-for-mail Return-Path: X-Original-To: python-list@python.org Delivered-To: python-list@mail.python.org X-Spam-Status: OK 0.003 X-Spam-Evidence: '*H*': 0.99; '*S*': 0.00; 'argument': 0.04; 'subject:skip:s 10': 0.05; 'alignment': 0.07; 'classes.': 0.07; 'padding': 0.07; 'pretend': 0.07; "object's": 0.09; 'pointless': 0.09; 'subject:language': 0.09; 'to:addr:comp.lang.python': 0.09; 'cc:addr:python-list': 0.10; 'language': 0.14; '(the': 0.15; 'anyways,': 0.16; 'classes)': 0.16; 'cryptic.': 0.16; 'formatting.': 0.16; 'hierarchy': 0.16; 'operators,': 0.16; 'readable': 0.16; 'subject:joining': 0.16; 'wrote:': 0.17; 'define': 0.20; 'do.': 0.21; 'supposed': 0.21; 'defined': 0.22; 'cc:2**0': 0.23; 'somewhere': 0.24; 'thus': 0.24; 'cc:no real name:2**0': 0.24; 'cc:addr:python.org': 0.25; 'header:In-Reply- To:1': 0.25; 'header:User-Agent:1': 0.26; 'supported': 0.26; '(as': 0.27; 'object,': 0.27; 'subject:list': 0.28; 'colon': 0.29; 'proposing': 0.29; 'class': 0.29; "i'm": 0.29; 'classes': 0.30; "skip:' 10": 0.30; 'lists': 0.31; "can't": 0.34; 'changed': 0.34; 'received:google.com': 0.34; 'done': 0.34; 'list': 0.35; 'said,': 0.35; 'received:209.85': 0.35; 'something': 0.35; 'method': 0.36; "i'll": 0.36; 'should': 0.36; 'thank': 0.36; 'being': 0.37; 'received:209': 0.37; 'far': 0.37; 'subject:: ': 0.38; 'fact': 0.38; 'object': 0.38; 'subject:-': 0.40; 'think': 0.40; 'your': 0.60; 'most': 0.61; 'first': 0.61; 'kind': 0.61; "you'll": 0.62; 'back': 0.62; '(that': 0.62; 'customized': 0.64; 'charset:windows-1252': 0.65; 'box,': 0.69; 'lack': 0.71; 'obvious': 0.71; "it'd": 0.84; 'it\x92s': 0.84; 'received:209.85.213.184': 0.91; 'temps': 0.91; 'old.': 0.95 Newsgroups: comp.lang.python Date: Sat, 10 Nov 2012 13:11:10 -0800 (PST) In-Reply-To: Complaints-To: groups-abuse@google.com Injection-Info: glegroupsg2000goo.googlegroups.com; posting-host=2.229.207.3; posting-account=f2kSKwoAAACp-DC0NIIB3ltNkhvqmHjp References: <92ada057-5a72-4186-bd22-4ccb600b8e45@googlegroups.com> <7xwqxt765m.fsf@ruckus.brouhaha.com> User-Agent: G2/1.0 X-Google-Web-Client: true X-Google-IP: 2.229.207.3 MIME-Version: 1.0 Subject: Re: Format specification mini-language for list joining From: Tobia Conforto To: comp.lang.python@googlegroups.com Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable Cc: python-list@python.org X-BeenThere: python-list@python.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: General discussion list for the Python programming language List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Message-ID: Lines: 32 NNTP-Posting-Host: 2001:888:2000:d::a6 X-Trace: 1352581872 news.xs4all.nl 6945 [2001:888:2000:d::a6]:48635 X-Complaints-To: abuse@xs4all.nl Xref: csiph.com comp.lang.python:33104 Kwpolska wrote: > > out =3D 'Temperatures: {0:", ":.1f} Celsius'.format(temps) >=20 > [...] your format is cryptic. Thank you for your criticism, I'll think it over. The reason I find it read= able (-enough) is because even without knowing what format language is supp= orted by the temps object, you can tell that "it" (the 0th argument in this= case) is what's going to be serialized in that place. Everything after the first colon is game anyways, meaning you'll have to lo= ok it up in the docs, because it's defined somewhere in the class hierarchy= of the object being serialized. The fact that 99% of classes don't define = a __format__ method and thus fall back on object's implementation, with it'= s alignment and padding operators, is IMHO irrelevant. It's still something= you can't pretend to know out of the box, because it's supposed to be cust= omizable by classes. Knowing this, if you know that the temps object is a list of floats, then I= think it'd be pretty obvious what the ", " and the :.1f should do. > As I said, it=92s hard to even get this one changed=20 > because str.format is 4 years old. Again, I beg to differ. I'm not proposing any change to format (that would = be madness). What I'm proposing is the addition of a customized __format__ = method to a few types, namely lists and sequences, that currently lack it (= as do 99% of classes) and fall back to object's implementation. Which is ki= nd of pointless with lists, as joining is by far the thing most often done = to them when formatting. Tobia