Path: csiph.com!usenet.pasdenom.info!news.redatomik.org!newsfeed.xs4all.nl!newsfeed2.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 0.035 X-Spam-Evidence: '*H*': 0.93; '*S*': 0.00; 'builtin': 0.07; 'indices': 0.07; 'subject:How': 0.09; 'len(x)': 0.09; 'slices': 0.09; 'index': 0.13; 'wed,': 0.15; 'selects': 0.16; 'sequence.': 0.16; 'subject:access': 0.16; 'wrote:': 0.16; 'am,': 0.23; '2015': 0.23; 'seems': 0.24; 'header:In-Reply-To:1': 0.24; 'raise': 0.24; 'least': 0.27; 'sequence': 0.27; 'message-id:@mail.gmail.com': 0.28; 'subject:list': 0.28; 'implied': 0.29; 'types.': 0.29; 'certainly': 0.31; "can't": 0.32; 'url:python': 0.33; 'rule': 0.33; 'received:google.com': 0.34; 'to:addr:python-list': 0.35; 'something': 0.35; 'but': 0.36; 'url:org': 0.36; 'thanks': 0.36; 'url:library': 0.36; 'subject:: ': 0.37; 'tue,': 0.38; 'means': 0.39; 'pm,': 0.39; 'enough': 0.39; 'url:docs': 0.39; 'to:addr:python.org': 0.39; 'sure': 0.40; 'subject:the': 0.40; 'url:3': 0.60; 'learn': 0.60; 'even': 0.61; 'entire': 0.61; 'matter': 0.63; 'above,': 0.63; 'stated': 0.70; 'to:name:python': 0.84; 'utc+5:30,': 0.84; 'visually': 0.84 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :content-type; bh=UMhaRwmrsad35Aj0TlTYqss7wAh3S4l59c7yJktnDbA=; b=j+Phw8wKNTYBnex04ySpnTgjzjqafbPkWgonAzAhsVfUWPOMNvWY3inME8T13UYERm VWX7Em/zW1Q0FxWrIfIsXqK57DS+TquCeqdBsqwpnx/qPA+md/5Wn3R2imeCs9qgXYuG /myqKJy90MYmbx+g+IgRRWun16h8mxwoP9c0bPc/OfPMZ7dgvml+mM5zqOLpc9ljzu++ a6bZOsLP83bL7Glh30ArbpepP2o5x+R3kNVMFDxeIIoFbRzAPPHzR5Z+KS5sEZS4zE05 WQLO+K8B73yw+gP6+N9qbf6iOWQQt8gQwvlAwkUGBHeGvyQiTCwaJRRXvZ71ukgABY6n HQ6A== X-Received: by 10.42.72.132 with SMTP id o4mr1121290icj.20.1433371021781; Wed, 03 Jun 2015 15:37:01 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <11005554-e89f-407c-8720-fae1bb3fced8@googlegroups.com> References: <18a4709f-47c8-41f7-87d5-08bbb00166b6@googlegroups.com> <11005554-e89f-407c-8720-fae1bb3fced8@googlegroups.com> From: Ian Kelly Date: Wed, 3 Jun 2015 16:36:21 -0600 Subject: Re: How to access the low digits of a list To: Python Content-Type: text/plain; charset=UTF-8 X-BeenThere: python-list@python.org X-Mailman-Version: 2.1.20+ 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: 23 NNTP-Posting-Host: 2001:888:2000:d::a6 X-Trace: 1433371024 news.xs4all.nl 2910 [2001:888:2000:d::a6]:39760 X-Complaints-To: abuse@xs4all.nl Xref: csiph.com comp.lang.python:92010 On Wed, Jun 3, 2015 at 3:08 PM, Rustom Mody wrote: > On Tuesday, June 2, 2015 at 7:50:58 PM UTC+5:30, Ian wrote: >> On Tue, Jun 2, 2015 at 6:35 AM, Rustom Mody wrote: >> > For that matter even this works >> > But I am not sure whats happening or that I like it >> > >> >>>> [x[-2:] for x in lines] >> > ['12', '42', '49', '56', '25', '36', '49', '64', '81', '00'] >> >> x[-2:] selects all items in the sequence with index i such that len(x) >> - 2 <= i < len(x). For a sequence of length 2 or less, that's the >> entire sequence. > > Thanks -- learn something > So it means that indices can give indexerror; slices cannot? > Seems fair enough put that way, but is visually counterintuitive Yes. The rule I paraphrased above is stated at https://docs.python.org/3/library/stdtypes.html#common-sequence-operations -- scroll down to note 4. I don't know if there's anything that clearly states that sequence slicing can't raise IndexError, but it is at least implied by the above, and it is certainly true of all builtin sequence types.