Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
Groups > comp.lang.python > #15742
| Path | csiph.com!x330-a1.tempe.blueboxinc.net!usenet.pasdenom.info!weretis.net!feeder1.news.weretis.net!feeder.erje.net!newsfeed.xs4all.nl!newsfeed5.news.xs4all.nl!xs4all!post.news.xs4all.nl!not-for-mail |
|---|---|
| Return-Path | <rosuav@gmail.com> |
| X-Original-To | python-list@python.org |
| Delivered-To | python-list@mail.python.org |
| X-Spam-Status | OK 0.014 |
| X-Spam-Evidence | '*H*': 0.97; '*S*': 0.00; '"if': 0.04; 'defaults': 0.07; 'compares': 0.09; 'am,': 0.12; '16,': 0.15; 'argument': 0.15; 'boolean': 0.16; 'compact': 0.16; 'from:addr:rosuav': 0.16; 'from:name:chris angelico': 0.16; 'none"': 0.16; 'quicker': 0.16; 'received:209.85.213.174': 0.16; 'received:mail- yx0-f174.google.com': 0.16; 'subject:import': 0.16; 'wed,': 0.17; 'wrote:': 0.18; 'header:In-Reply-To:1': 0.23; 'testing': 0.24; 'variable': 0.24; 'message-id:@mail.gmail.com': 0.29; 'equality': 0.30; 'nov': 0.31; 'value.': 0.32; 'to:addr:python-list': 0.32; 'done': 0.33; 'probably': 0.34; 'david': 0.34; 'none': 0.36; 'two': 0.37; 'could': 0.38; 'received:google.com': 0.38; 'some': 0.38; 'received:209.85': 0.38; 'e.g.': 0.38; 'should': 0.39; "it's": 0.39; 'subject:: ': 0.39; 'might': 0.39; 'to:addr:python.org': 0.39; 'received:209': 0.40; 'really': 0.40; 'more': 0.60; '2011': 0.62; 'hand,': 0.76; 'beware': 0.84; 'container)': 0.84; 'riley': 0.84; '\xa0also,': 0.84 |
| DKIM-Signature | v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type:content-transfer-encoding; bh=K8bPFFWKqV9q5Jj3k0/nmSbn3hzJv9DAog2/YACIuZo=; b=EPK42LjaiKDMXJp6bXMwKYxAId4HJ8tyCKeS4PJc/seC2u8uqEQ7O4/tQ0WqWro+JV HNCjdTV16OUapasRlkP/9jvbaRVG8JVfBMuTYbCWVolG8sy86Rs4BeFN7JOoIYsPpkAq LL4COkSq2BLwA1bgQZI2KM5hu6RLKkRXtn7Ww= |
| MIME-Version | 1.0 |
| In-Reply-To | <F8266E63-F932-4216-9E33-8333C1D62E43@gmail.com> |
| References | <CAC82khmG+zH3Cd5pRfou+0FED18MHfizLzJL4EM+V+Pw+q17+w@mail.gmail.com> <CALvWhxvc=Ng28YeiL0Onv9YCixfQtOqgLENWJqYgoRSYvo_juA@mail.gmail.com> <CAC82khn3WBjXY7podVq6RX0d0j38w1vbtN3fNOCSGLcu2X_jOw@mail.gmail.com> <D97140E4-9B09-4EAE-BB92-0F038FCDBA5A@gmail.com> <4EC2B656.7050902@sequans.com> <0601B8C7-9AEF-443A-A149-0F7D356345EF@gmail.com> <CAPTjJmrP7fMg9UfxdsR=5j6EW4yFKf8gR4xYQD5zDwMUVxdmjw@mail.gmail.com> <F8266E63-F932-4216-9E33-8333C1D62E43@gmail.com> |
| Date | Wed, 16 Nov 2011 08:34:02 +1100 |
| Subject | Re: suppressing import errors |
| From | Chris Angelico <rosuav@gmail.com> |
| To | python-list@python.org |
| Content-Type | text/plain; charset=ISO-8859-1 |
| Content-Transfer-Encoding | quoted-printable |
| X-BeenThere | python-list@python.org |
| X-Mailman-Version | 2.1.12 |
| Precedence | list |
| List-Id | General discussion list for the Python programming language <python-list.python.org> |
| List-Unsubscribe | <http://mail.python.org/mailman/options/python-list>, <mailto:python-list-request@python.org?subject=unsubscribe> |
| List-Archive | <http://mail.python.org/pipermail/python-list> |
| List-Post | <mailto:python-list@python.org> |
| List-Help | <mailto:python-list-request@python.org?subject=help> |
| List-Subscribe | <http://mail.python.org/mailman/listinfo/python-list>, <mailto:python-list-request@python.org?subject=subscribe> |
| Newsgroups | comp.lang.python |
| Message-ID | <mailman.2751.1321392845.27778.python-list@python.org> (permalink) |
| Lines | 20 |
| NNTP-Posting-Host | 2001:888:2000:d::a6 |
| X-Trace | 1321392845 news.xs4all.nl 6901 [2001:888:2000:d::a6]:45157 |
| X-Complaints-To | abuse@xs4all.nl |
| Xref | x330-a1.tempe.blueboxinc.net comp.lang.python:15742 |
Show key headers only | View raw
On Wed, Nov 16, 2011 at 8:20 AM, David Riley <fraveydank@gmail.com> wrote: > Comparisons to singletons like None should always be done with > 'is' or 'is not', never the equality operators. > > Also, beware of writing "if x" when you really mean "if x is not None" > -- e.g. when testing whether a variable or argument that defaults to > None was set to some other value. The other value might have a type > (such as a container) that could be false in a boolean context! It's probably quicker to execute "if x is None" than "if x" (presumably the former just compares the two pointers). On the other hand, it's more compact to leave off the "is None". And on the gripping hand, neither "quicker to execute" nor "more compact" equates to "more Pythonic". ChrisA
Back to comp.lang.python | Previous | Next | Find similar | Unroll thread
Re: suppressing import errors Chris Angelico <rosuav@gmail.com> - 2011-11-16 08:34 +1100
csiph-web