Path: csiph.com!usenet.pasdenom.info!weretis.net!feeder4.news.weretis.net!rt.uk.eu.org!newsfeed.xs4all.nl!newsfeed4a.news.xs4all.nl!xs4all!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 0.002 X-Spam-Evidence: '*H*': 1.00; '*S*': 0.00; 'argument': 0.05; 'element': 0.07; 'omit': 0.09; 'parsing': 0.09; 'throws': 0.09; 'cc:addr:python-list': 0.11; 'python': 0.11; '-tkc': 0.16; 'from:addr:python.list': 0.16; 'from:addr:tim.thechases.com': 0.16; 'from:name:tim chase': 0.16; 'otherwise:': 0.16; 'parentheses': 0.16; 'subject:Remove': 0.16; 'subject:python.': 0.16; 'syntaxerror:': 0.16; 'tuple,': 0.16; 'tuples,': 0.16; 'unpacking': 0.16; 'wrote:': 0.18; 'written': 0.21; '>>>': 0.22; 'cc:addr:python.org': 0.22; 'tend': 0.24; 'cc:2**0': 0.24; 'cc:no real name:2**0': 0.24; 'pass': 0.26; 'header:In-Reply-To:1': 0.27; 'function': 0.29; 'easier': 0.31; '"",': 0.31; 'values.': 0.31; 'file': 0.32; "i'd": 0.34; 'subject:from': 0.34; 'but': 0.35; 'charset:us-ascii': 0.36; 'though,': 0.39; 'sure': 0.39; 'read': 0.60; 'expression': 0.60; 'more': 0.64; 'sole': 0.78; 'ambiguous': 0.84; 'received:50.22': 0.84; 'to:addr:ntlworld.com': 0.84; 'whereas': 0.91 Date: Fri, 21 Feb 2014 08:00:32 -0600 From: Tim Chase To: Alister Subject: Re: Remove comma from tuples in python. In-Reply-To: References: <8ca893cc-c010-486b-ace3-070ff7ffdac8@googlegroups.com> X-Mailer: Claws Mail 3.8.1 (GTK+ 2.24.10; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - boston.accountservergroup.com X-AntiAbuse: Original Domain - python.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - tim.thechases.com X-Get-Message-Sender-Via: boston.accountservergroup.com: authenticated_id: tim@thechases.com 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: , Newsgroups: comp.lang.python Message-ID: Lines: 39 NNTP-Posting-Host: 2001:888:2000:d::a6 X-Trace: 1392991207 news.xs4all.nl 2850 [2001:888:2000:d::a6]:37392 X-Complaints-To: abuse@xs4all.nl Xref: csiph.com comp.lang.python:66831 On 2014-02-21 09:29, Alister wrote: > > >>> seriesxlist1 = ((0.0,), (0.01,), (0.02,)) > > >>> x2 = [x*x for (x,) in seriesxlist1] > > > > I tend to omit those parentheses and use just the comma: > > > > >>> x2 = [x*x for x, in seriesxlist1] > > I had not though of using unpacking in this way & would have written > > x2= [x[0]**2 for x in serisexlist1] > > I am not sure which is easier to read in this instance (single > element tupple) but unpacking would definitely be the way to go if > the tupple had multiple values. With the single-value tuple, I tend to find the parens make it more readable, so I'd go with [x*x for (x,) in lst] whereas if they were multi-value tuples, I tend to omit the parens: [x*y for x,y in lst] though, tangentially, Python throws a SyntaxError if you try and pass a generator to a function without extra outer parens because it makes parsing them ambiguous otherwise: >>> x = sum(a+b for a, b in lst, 10) File "", line 1 SyntaxError: Generator expression must be parenthesized if not sole argument >>> x = sum((a+b) for a,b in lst), 10) [no error] -tkc