Path: csiph.com!v102.xanadu-bbs.net!xanadu-bbs.net!news.mixmin.net!de-l.enfer-du-nord.net!feeder1.enfer-du-nord.net!newsfeed.eweka.nl!eweka.nl!feeder3.eweka.nl!newsfeed.xs4all.nl!newsfeed6.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 0.005 X-Spam-Evidence: '*H*': 0.99; '*S*': 0.00; 'else:': 0.03; 'removes': 0.05; 'puts': 0.07; 'python': 0.09; '[];': 0.09; 'happen?': 0.09; 'def': 0.10; 'slightly': 0.15; '#this': 0.16; '-1:': 0.16; 'string': 0.17; 'wrote:': 0.17; 'runs': 0.22; 'statement': 0.23; 'seems': 0.23; 'second': 0.24; 'header:In-Reply-To:1': 0.25; 'header:User-Agent:1': 0.26; 'noticed': 0.28; 'run': 0.28; 'finds': 0.29; 'str': 0.29; 'function': 0.30; 'code': 0.31; "skip:' 20": 0.32; 'print': 0.32; 'function.': 0.33; 'problem': 0.33; 'to:addr:python-list': 0.33; 'hi,': 0.33; 'another': 0.33; 'version': 0.34; 'list': 0.35; 'identified': 0.35; 'does': 0.37; 'being': 0.37; 'why': 0.37; 'subject:: ': 0.38; 'comment': 0.38; 'to:addr:python.org': 0.39; 'takes': 0.39; 'received:192': 0.39; 'notice': 0.39; 'received:192.168': 0.40; 'your': 0.60; 'email addr:gmail.com': 0.63; 'making': 0.64; 'here': 0.65; 'migrating': 0.91 X-SENDER-IP: [213.112.50.224] X-LISTENER: [smtp.bredband.net] X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AtseAEuoKlDVcDLgPGdsb2JhbAANOIo7sAIBAQEBN4JUAQEBAQM4QBELGAkWDwkDAgECAQ8iFBMGAgEBh3oDpFiKbw2JToohg3mDHAOLMYhHiBuEQodn X-IronPort-AV: E=Sophos;i="4.77,768,1336341600"; d="scan'208";a="393784454" Date: Tue, 14 Aug 2012 21:40:10 +0200 From: Virgil Stokes User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:15.0) Gecko/20120808 Thunderbird/15.0 MIME-Version: 1.0 To: python-list@python.org Subject: Re: Strange behavior References: <1a1834ae-2b4a-473f-b626-f37a17588199@googlegroups.com> In-Reply-To: <1a1834ae-2b4a-473f-b626-f37a17588199@googlegroups.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-BeenThere: python-list@python.org X-Mailman-Version: 2.1.12 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: 82 NNTP-Posting-Host: 2001:888:2000:d::a6 X-Trace: 1344973216 news.xs4all.nl 6906 [2001:888:2000:d::a6]:59833 X-Complaints-To: abuse@xs4all.nl Xref: csiph.com comp.lang.python:27056 On 2012-08-14 17:38, light1quark@gmail.com wrote: > Hi, I am migrating from PHP to Python and I am slightly confused. > > I am making a function that takes a startingList, finds all the strings in the list that begin with 'x', removes those strings and puts them into a xOnlyList. > > However if you run the code you will notice only one of the strings beginning with 'x' is removed from the startingList. > If I comment out 'startingList.remove(str);' the code runs with both strings beginning with 'x' being put in the xOnlyList. > Using the print statement I noticed that the second string that begins with 'x' isn't even identified by the function. Why does this happen? > > def testFunc(startingList): > xOnlyList = []; > for str in startingList: > if (str[0] == 'x'): > print str; > xOnlyList.append(str) > startingList.remove(str) #this seems to be the problem > print xOnlyList; > print startingList > testFunc(['xasd', 'xjkl', 'sefwr', 'dfsews']) > > #Thanks for your help! You might find the following useful: def testFunc(startingList): xOnlyList = []; j = -1 for xl in startingList: if (xl[0] == 'x'): xOnlyList.append(xl) else: j += 1 startingList[j] = xl if j == -1: startingList = [] else: del startingList[j:-1] return(xOnlyList) testList1 = ['xasd', 'xjkl', 'sefwr', 'dfsews'] testList2 = ['xasd', 'xjkl', 'xsefwr', 'xdfsews'] testList3 = ['xasd', 'jkl', 'sefwr', 'dfsews'] testList4 = ['asd', 'jkl', 'sefwr', 'dfsews'] xOnlyList = testFunc(testList1) print 'xOnlyList = ',xOnlyList print 'testList = ',testList1 xOnlyList = testFunc(testList2) print 'xOnlyList = ',xOnlyList print 'testList = ',testList2 xOnlyList = testFunc(testList3) print 'xOnlyList = ',xOnlyList print 'testList = ',testList3 xOnlyList = testFunc(testList4) print 'xOnlyList = ',xOnlyList print 'testList = ',testList4 And here is another version using list comprehension that I prefer testList1 = ['xasd', 'xjkl', 'sefwr', 'dfsews'] testList2 = ['xasd', 'xjkl', 'xsefwr', 'xdfsews'] testList3 = ['xasd', 'jkl', 'sefwr', 'dfsews'] testList4 = ['asd', 'jkl', 'sefwr', 'dfsews'] def testFunc2(startingList): return([x for x in startingList if x[0] == 'x'], [x for x in startingList if x[0] != 'x']) xOnlyList,testList = testFunc2(testList1) print xOnlyList print testList xOnlyList,testList = testFunc2(testList2) print xOnlyList print testList xOnlyList,testList = testFunc2(testList3) print xOnlyList print testList xOnlyList,testList = testFunc2(testList4) print xOnlyList print testList