Path: csiph.com!usenet.pasdenom.info!weretis.net!feeder4.news.weretis.net!feeds.phibee-telecom.net!newsfeed.xs4all.nl!newsfeed1.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 0.044 X-Spam-Evidence: '*H*': 0.91; '*S*': 0.00; 'none,': 0.07; 'subject:would': 0.07; 'exception,': 0.09; 'exception.': 0.09; 'happen?': 0.09; 'cc:addr:python-list': 0.11; 'from:addr:rosuav': 0.16; 'from:name:chris angelico': 0.16; 'function?': 0.16; 'none.': 0.16; 'readable': 0.16; 'exception': 0.16; 'wrote:': 0.18; 'basically': 0.19; 'thu,': 0.19; 'seems': 0.21; 'feb': 0.22; 'cc:addr:python.org': 0.22; '"you': 0.24; 'question': 0.24; 'cc:2**0': 0.24; 'header:In-Reply-To:1': 0.27; 'wondering': 0.29; 'raise': 0.29; "doesn't": 0.30; 'matching': 0.30; 'especially': 0.30; 'message-id:@mail.gmail.com': 0.30; 'asked': 0.31; 'getting': 0.31; 'file': 0.32; 'but': 0.35; 'received:google.com': 0.35; 'really': 0.36; 'subject:?': 0.36; 'should': 0.36; 'jason': 0.38; 'files': 0.38; 'pm,': 0.38; 'recent': 0.39; 'does': 0.39; 'either': 0.39; 'how': 0.40; 'skip:u 10': 0.60; 'is.': 0.60; 'most': 0.60; 'matter': 0.61; 'simply': 0.61; 'name': 0.63; 'such': 0.63; 'situation': 0.65; 'unusual': 0.74; '2015': 0.84; 'timestamps,': 0.84; 'subject:you': 0.87; 'to:none': 0.92; 'remember,': 0.93; 'instant': 0.97 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:cc :content-type; bh=FooTVomHLMvQMmyk/KG7BdDZAqW+c0LDqOCv0tL3qGs=; b=xBFq2d+9GGl98L0+LOTtbHKNzzH6yMEC6A2yOchTfjqnYYtUbt3lemTqCJ/PdMz9DK KVanZz+Brx4VUoe2R4Ci0+oBTS5thpHKqZ+0PTSHOJPHR9+l9KEjpG8seUGXW5CRB4bY hwqPrx/CKWrLz1UrkTEQaStte3Dhfql9Qav59NOAPVIYAecmelXjmvUyS2/bOV7rlyy2 A6l08mxGxPyDMxCE4Rvr2tjTY6eHoKwRggq9qkCbbzPO2KHIRHEhMoRXdeQVl2mYLOap DpHRj+umjKnZmakPWatByfraP0DzQ4Cvw6PsVXaLXq5GzeOXxLY24qXuRHU1u3R9M5lU 2kig== MIME-Version: 1.0 X-Received: by 10.50.114.4 with SMTP id jc4mr7563630igb.14.1424322602537; Wed, 18 Feb 2015 21:10:02 -0800 (PST) In-Reply-To: References: Date: Thu, 19 Feb 2015 16:10:02 +1100 Subject: Re: What behavior would you expect? From: Chris Angelico Cc: python-list Content-Type: text/plain; charset=UTF-8 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: 38 NNTP-Posting-Host: 2001:888:2000:d::a6 X-Trace: 1424322611 news.xs4all.nl 2949 [2001:888:2000:d::a6]:51330 X-Complaints-To: abuse@xs4all.nl Xref: csiph.com comp.lang.python:85863 On Thu, Feb 19, 2015 at 3:44 PM, Jason Friedman wrote: > I have need to search a directory and return the name of the most recent > file matching a given pattern. Given a directory with these files and > timestamps, > > q.pattern1.abc Feb 13 > r.pattern1.cdf Feb 12 > s.pattern1.efg Feb 10 > t.pattern2.abc Feb 13 > u.pattern2.xyz Feb 14 > v.pattern2.efg Feb 10 > > calling my_function("/path/to/dir", "pattern1") will return q.pattern1.abc > and calling my_function("/path/to/dir", "pattern2") will return > u.pattern2.xyz. That seems reasonable, and well-defined. > My question is, what would be a reasonable behavior/result/return value if: > 1. "/path/to/dir" does not exist or is not readable Raise an exception. Or, better still, just allow the exception to bubble. > 2. no files match the given pattern Either return None, or raise an exception, depending on how "normal" this state is. Is it simply a matter of "you asked for something, but you got nothing"? Then return None. Is it a really unusual situation that should basically never happen? Then raise an exception, so you get an instant report with no wondering "why am I getting these strange TypeErrors". > Also, what would be a reasonable name for such a function? newest_file_matching() seems decent. Remember, it doesn't have to be especially short. ChrisA