And for those interested in how I received Laura's message (the one I replied to):
---<--------------------cut here---------------start------------------->--- Path: news.gmane.org!not-for-mail From: Laura Creighton <[email protected]> Newsgroups: gmane.comp.python.general Subject: Re: scalar vs array and program control Date: Sat, 25 Jul 2015 14:44:43 +0200 Lines: 44 Approved: [email protected] Message-ID: <[email protected]> References: <[email protected]><[email protected]> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit X-Trace: ger.gmane.org 1437828370 13839 80.91.229.3 (25 Jul 2015 12:46:10 GMT) X-Complaints-To: [email protected] NNTP-Posting-Date: Sat, 25 Jul 2015 12:46:10 +0000 (UTC) Cc: Seb <[email protected]> To: [email protected] Original-X-From: [email protected] Sat Jul 25 14:46:03 2015 Return-path: <[email protected]> Envelope-to: [email protected] Original-Received: from mail.python.org ([82.94.164.166]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from <[email protected]>) id 1ZIyq2-0002GT-Ta for [email protected]; Sat, 25 Jul 2015 14:46:03 +0200 Original-Received: from albatross.python.org (localhost [127.0.0.1]) by mail.python.org (Postfix) with ESMTP id 3mdnFQ2j3LzPgt for <[email protected]>; Sat, 25 Jul 2015 14:46:02 +0200 (CEST) X-Original-To: [email protected] Delivered-To: [email protected] Original-Received: from albatross.python.org (localhost [127.0.0.1]) by mail.python.org (Postfix) with ESMTP id 3mdnD81R8jzPZj for <[email protected]>; Sat, 25 Jul 2015 14:44:56 +0200 (CEST) X-Spam-Status: OK 0.000 X-Spam-Evidence: '*H*': 1.00; '*S*': 0.00; 'revision': 0.05; 'chunk': 0.07; 'exception.': 0.07; 'smallest': 0.07; 'thats': 0.07; 'valueerror:': 0.07; 'received:openend.se': 0.09; 'received:theraft.openend.se': 0.09; 'skip:t 60': 0.09; 'ignore': 0.14; 'things.': 0.15; '>try:': 0.16; 'from:addr:lac': 0.16; 'from:addr:openend.se': 0.16; 'from:name:laura creighton': 0.16; 'happily': 0.16; 'message-id:@fido.openend.se': 0.16; 'received:89.233': 0.16; 'received:89.233.217': 0.16; 'received:89.233.217.133': 0.16; 'received:fido': 0.16; 'received:fido.openend.se': 0.16; 'subject:array': 0.16; 'subject:program': 0.16; 'try/except': 0.16; 'laura': 0.18; 'stick': 0.18; 'try:': 0.18; 'cc:2**0': 0.20; 'posted': 0.21; 'work,': 0.21; 'pass': 0.22; 'errors': 0.23; 'forgot': 0.23; 'this:': 0.23; 'cc:addr:gmail.com': 0.24; 'written': 0.24; 'header :In-Reply-To:1': 0.24; 'skip:m 30': 0.27; 'e Original-Received: from localhost (HELO mail.python.org) (127.0.0.1) by albatross.python.org with SMTP; 25 Jul 2015 14:44:56 +0200 Original-Received: from theraft.openend.se (theraft.ipv6.openend.se [IPv6:2001:16d8:ffca::2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.python.org (Postfix) with ESMTPS for <[email protected]>; Sat, 25 Jul 2015 14:44:55 +0200 (CEST) Original-Received: from fido.openend.se ([email protected] [89.233.217.133]) by theraft.openend.se (8.14.4/8.14.4/Debian-4) with ESMTP id t6PCihR6024800 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Sat, 25 Jul 2015 14:44:45 +0200 Original-Received: from fido (lac@localhost [127.0.0.1]) by fido.openend.se (8.14.9/8.14.9/Debian-1) with ESMTP id t6PCihmd023479; Sat, 25 Jul 2015 14:44:43 +0200 In-Reply-To: Message from Laura Creighton <[email protected]> of "Sat, 25 Jul 2015 13:01:21 +0200." <[email protected]> Content-ID: <23477.1437828283.1@fido> X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.3.9 (theraft.openend.se [89.233.217.130]); Sat, 25 Jul 2015 14:44:45 +0200 (CEST) X-BeenThere: [email protected] X-Mailman-Version: 2.1.20+ Precedence: list List-Id: General discussion list for the Python programming language <python-list.python.org> List-Unsubscribe: <https://mail.python.org/mailman/options/python-list>, <mailto:[email protected]?subject=unsubscribe> List-Archive: <http://mail.python.org/pipermail/python-list/> List-Post: <mailto:[email protected]> List-Help: <mailto:[email protected]?subject=help> List-Subscribe: <https://mail.python.org/mailman/listinfo/python-list>, <mailto:[email protected]?subject=subscribe> Errors-To: [email protected] Original-Sender: "Python-list" <[email protected]> Xref: news.gmane.org gmane.comp.python.general:780612 Archived-At: <http://permalink.gmane.org/gmane.comp.python.general/780612> And because I was rushed and posted without revision I left out something important. >So this is, quite likely, the pattern that you are looking for: > >try: > all_your_code_which_is_happy_with_non_scalars >except WhateverErrorPythonGivesYouWhenYouTryThisWithScalars: > whatever_you_want_to_do_when_this_happens > >This is the usual way to do things. I forgot to tell you that you are supposed to stick the try/except around the smallest chunk of code that you expect to get the exception. So you write this as code_you_expect_always_to_work more_code_you_expect_always_to_work try: these_four_lines_of_code_that_will_be_unhappy_if_its_a_scalar except ValueError: # whatever kind of error the real error is whatever_you_want_to_do_when_that_happens The reason is that if you get any Value Errors in the part of the code you always expect to work, then you don't want your program to run happily along running the code for 'its a scalar'. You don't want to hide real errors here. The other thing I forgot to mention is that sometimes you don't want to do anything but ignore any errors of this sort. Thats written like this: code_you_expect_always_to_work more_code_you_expect_always_to_work try: these_four_lines_of_code_that_will_be_unhappy_if_its_a_scalar except ValueError: pass # just ignore it Laura ---<--------------------cut here---------------end--------------------->--- Cheers, -- Seb -- https://mail.python.org/mailman/listinfo/python-list
