Path: csiph.com!usenet.pasdenom.info!aioe.org!news.stack.nl!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 0.000 X-Spam-Evidence: '*H*': 1.00; '*S*': 0.00; 'else:': 0.03; 'value,': 0.04; 'subject:Python': 0.06; "'',": 0.07; 'element': 0.07; 'ignored': 0.07; 'json': 0.07; 'nested': 0.07; 'subject:Question': 0.07; 'transform': 0.07; 'string': 0.09; '===': 0.09; 'pgp': 0.09; 'preferable': 0.09; 'try:': 0.09; 'valueerror:': 0.09; 'variant': 0.09; 'cc:addr:python-list': 0.11; 'martin': 0.11; 'python': 0.11; '-----begin': 0.16; '-----end': 0.16; 'c_int': 0.16; 'coerced': 0.16; 'gnupg': 0.16; 'hash:': 0.16; 'nesting': 0.16; 'personally,': 0.16; 'practice?': 0.16; 'sha1': 0.16; 'skip:j 60': 0.16; 'ignore': 0.16; 'language': 0.16; 'thanks,': 0.17; 'wrote:': 0.18; 'message-----': 0.19; 'example': 0.22; 'cc:addr:python.org': 0.22; 'integer': 0.24; 'necessary.': 0.24; 'fine': 0.24; 'cc:2**0': 0.24; 'options': 0.25; 'pass': 0.26; 'signed': 0.27; 'values': 0.27; 'header:In-Reply-To:1': 0.27; 'function': 0.29; "doesn't": 0.30; 'message-id:@mail.gmail.com': 0.30; 'url:mailman': 0.30; 'code': 0.31; 'exceptions': 0.31; 'skip:i 60': 0.31; 'this.': 0.32; 'another': 0.32; 'url:python': 0.33; 'maybe': 0.34; 'except': 0.35; 'something': 0.35; 'received:google.com': 0.35; 'add': 0.35; 'there': 0.35; 'options:': 0.36; 'skip:s 60': 0.36; 'version:': 0.36; 'url:listinfo': 0.36; 'url:org': 0.36; 'should': 0.36; 'list': 0.37; 'e.g.': 0.38; 'does': 0.39; 'url:mail': 0.40; 'catch': 0.60; 'first': 0.61; 'more': 0.64; 'incoming': 0.72; 'skip:9 60': 0.91; 'to:none': 0.92 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=G2eZ1fckgobeNKPj+Lek89RKGcwM27ccuhpa1reLE7U=; b=h9BRqBSoovqEg3hG19cF/nFD+0VnYcqaQW5k/3P7hgo9fhZ0lNLtlCN/LG1N0iqwRd YoX896CqeaPfaYOZm6RepgTQA7RQ2xMiYEfCSD5RDx0hAXG30jDr+jKDummsHx/yld+m hbTMlebl8hf48gIWwMDddzE8uKNI+nc1aBGqrYGU5E6800CJEzd9nsQYU9jxpjiMy043 vD+7bNHmLagj1ZxtArxGdu59IseHZqnMI644VBqyF+39LNQcnh+LOx6DZ9HksiJhKWK6 NgcWdJ+ABVz9F7pPNlFtsXs2BRX4kFEF8UEX06mvfdVrmUKVyLSfVb61C/Jcu2hyOsrN U9Ig== MIME-Version: 1.0 X-Received: by 10.112.47.37 with SMTP id a5mr10789224lbn.31.1414583545846; Wed, 29 Oct 2014 04:52:25 -0700 (PDT) In-Reply-To: References: <406463d0-1287-49a2-b1ed-08a928db4b94@googlegroups.com> Date: Wed, 29 Oct 2014 12:52:25 +0100 Subject: Re: Python Style Question From: Rafael Romero Carmona Cc: "python-list@python.org" Content-Type: text/plain; charset=UTF-8 X-Mailman-Approved-At: Wed, 29 Oct 2014 12:59:13 +0100 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: 64 NNTP-Posting-Host: 2001:888:2000:d::a6 X-Trace: 1414583954 news.xs4all.nl 2978 [2001:888:2000:d::a6]:56060 X-Complaints-To: abuse@xs4all.nl Xref: csiph.com comp.lang.python:79909 2014-10-29 12:25 GMT+01:00 Martin Kemp : > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > On 29/10/2014 10:45, Anton wrote: >> Let's say I have an incoming list of values *l*. Every element of >> *l* can be one of the following options: 1) an integer value 2) a >> string in form of '', e.g. '7' 3) a string with a json >> serialization of an integer value, e.g. '"7"' 4) something else >> that should be ignored >> >> I need to transform this list into another list with values from >> options 1)-3) coerced to int. The code below should do this. >> >> >> Variant 1 === >> >> values = [] for c in l: # Case 1) or 2) try: c_int = int(c) except >> ValueError: pass else: values.add(c_int) continue >> >> # Case 3) try: c_int = int(json.loads(c)) except ValueError: pass >> else: values.add(c_int) continue >> >> === >> >> Is this code ugly? Does it follow EAFP? Am I missing something in >> language best practice? >> >> Or maybe below is more preferable way with a nested try...except >> clause? >> >> Variant 2 === values = [] for c in l: # Case 1) or 2) try: c_int = >> int(c) except ValueError: # Case 3) try: c_int = >> int(json.loads(c)) except ValueError: pass else: values.add(c_int) >> continue else: values.add(c_int) continue === >> >> Thanks, Anton. >> >> > > Your first example is perfectly fine and is EAFP > Actually it doesn't work because there is no add function and it doesn't catch the TypeError function to ignore other exceptions than ValueError. Doesn't it? I tested in Python 2.7.6 and 3.4. > Personally, I prefer to avoid nesting when it's not necessary. > > - -- > Martin Kemp (martin.kemp@ingg.com) > -----BEGIN PGP SIGNATURE----- > Version: GnuPG v2 > > iQEcBAEBAgAGBQJUUM7zAAoJEJ0Re0UIDzSucugIALn/zY8RdpP8iaMShHoszzqf > I0zl0mFHyqhNtwgQ0ZF7VGO+H+U0Dk8rhzTYOmEMzPTKNBGwll3fda9mOnrK9Xvp > 9gQjII6DyQIWH7Z3dLcLr2e1j8OMNUSL6UmAYs8urNSIKZLowdV3JI4G/bLyW0KS > y5Ko8dI6y5nOJ1P9XCmPTmags43UZfR8DrBUaAbzNcS8FGwmUE2KBkEhLQOvmpJi > jmMc7wMOpq0jL+XbA+7pHUqoVZ7w1tUFjuy9I3h45tgPuTFAFB0gX+FpE+oVgO5o > spQpVaOPEYN9ceLgHdKSxzdVIhOQLE6H/SYNHlsEW/ZNM6aR9n4yipgkOmtJ0+M= > =WzHA > -----END PGP SIGNATURE----- > -- > https://mail.python.org/mailman/listinfo/python-list