Moving from Python 2 to Python 3: A 4 page "cheat sheet"
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From: Mark Summerfield on 3 Dec 2009 03:13 On 2 Dec, 20:59, MRAB <pyt...(a)mrabarnett.plus.com> wrote: > Mark Summerfield wrote: > > On 2 Dec, 19:28, David H Wild <dhw...(a)talktalk.net> wrote: > >> In article > >> <351fcb4c-4e88-41b0-a0aa-b3d63832d...(a)e23g2000yqd.googlegroups.com>, > >> Mark Summerfield <l...(a)qtrac.plus.com> wrote: > > >>> I only just found out that I was supposed to give a different URL: > >>>http://www.informit.com/promotions/promotion.aspx?promo=137519 > >>> This leads to a web page where you can download the document (just by > >>> clicking the "Download Now" button), but if you _choose_ you can also > >>> enter your name and email to win some sort of prize. > >> There is a typographical fault on page 4 of this pdf file. The letter "P" > >> is missing from the word "Python" at the head of the comparison columns. > > Which is page 4? The page numbers are missing! (But the column titles > look OK.) :-) I didn't put page numbers or headers or footers on it---seemed redundant for such a short document. > > I can't see that problem---I've tried the PDF with evince, gv, > > acroread, and okular, and no missing "P" on page 4. I don't have a > > machine with RISC OS on it so I can't test on that environment! > >
From: Mark Summerfield on 3 Dec 2009 03:44 On 3 Dec, 01:17, Antoine Pitrou <solip...(a)pitrou.net> wrote: > Le Tue, 01 Dec 2009 06:03:36 -0800, Mark Summerfield a écrit : > > > I've produced a 4 page document that provides a very concise summary of > > Python 2<->3 differences plus the most commonly used new Python 3 > > features. It is aimed at existing Python 2 programmers who want to start > > writing Python 3 programs and want to use Python 3 idioms rather than > > those from Python 2 where the idioms differ. > [...] > > > It is available as a free PDF download (no registration or anything) > > from InformIT's website. Here's the direct link: > > This is great! > > Just one thing: > > « Copyright © Qtrac Ltd. 2009. All rights reserved » > > Might I suggest that you release it under a free license instead? > (such as the CC by, CC by-sa, or the Free Art License) > > Regards > > Antoine. Good idea---I'll try.
From: Wolodja Wentland on 3 Dec 2009 05:40 On Wed, Dec 02, 2009 at 08:03 -0800, Mark Summerfield wrote: > On Dec 2, 11:20 am, Wolodja Wentland <wentl...(a)cl.uni-heidelberg.de> > > It would be quite nice if you could mark all the Python 3 idioms that > > work in Python 2.X as well. This would allow readers that are still using > > Python 2.X and are used to the 'old way' to adapt their coding style > > accordingly. You could just add a little (2.X) after the idiom for > > example. > Yes it would be nice, but it isn't quite so simple. > To take sorted() as just one example, it was introduced in 2.4 so > arguably using it isn't valid/idiomatic for Python 2.x programs where > you care about backwards compatibility for the Python 2.x series... Yes, which is why you could include a 2.X and people who target, say current +/- 0.1 can choose their poison. > But my main reason for not wanting to do this is that the document is > aimed at people who want to write Python 3, not to encourage people to > stick with 2:-) I actually think that it is the other way round. People should get familiar with py3 features even if they are not yet ready to "abandon" py2 (yet). I also think that using some of the backported/supported features might spur interest in features that are 'py3 only' and therefore encourage the adoption of py3. It would also be nice to have a summary of things people can do *now* if they want to keep the changes from 2to3 to a minimum, which will be with us for some time. But that is not something *you* have to write .. :-) -- .''`. Wolodja Wentland <wentland(a)cl.uni-heidelberg.de> : :' : `. `'` 4096R/CAF14EFC `- 081C B7CD FF04 2BA9 94EA 36B2 8B7F 7D30 CAF1 4EFC
From: David H Wild on 2 Dec 2009 16:28 In article <9d290ad6-e0b8-4bfa-92c8-8209c7e933ec(a)a21g2000yqc.googlegroups.com>, Mark Summerfield <list(a)qtrac.plus.com> wrote: > > There is a typographical fault on page 4 of this pdf file. The letter > > "P" is missing from the word "Python" at the head of the comparison > > columns. > I can't see that problem---I've tried the PDF with evince, gv, > acroread, and okular, and no missing "P" on page 4. I don't have a > machine with RISC OS on it so I can't test on that environment! Using a different pdf reader, on the same machine, the letters are there. It's an odd thing, because it's only that one page that has the problem. Thanks, anyway. -- David Wild using RISC OS on broadband www.davidhwild.me.uk
From: Mark Summerfield on 3 Dec 2009 08:45
On 2 Dec, 21:28, David H Wild <dhw...(a)talktalk.net> wrote: > In article > <9d290ad6-e0b8-4bfa-92c8-8209c7e93...(a)a21g2000yqc.googlegroups.com>, > Mark Summerfield <l...(a)qtrac.plus.com> wrote: > > > > There is a typographical fault on page 4 of this pdf file. The letter > > > "P" is missing from the word "Python" at the head of the comparison > > > columns. > > I can't see that problem---I've tried the PDF with evince, gv, > > acroread, and okular, and no missing "P" on page 4. I don't have a > > machine with RISC OS on it so I can't test on that environment! > > Using a different pdf reader, on the same machine, the letters are there. > It's an odd thing, because it's only that one page that has the problem. I've never had a problem with my PDFs before. However I use the lout typesetting system and I suspect that it has some bugs relating to external links (which normally I don't use but which I've put in this particular document). Anyway, glad you found something that could read it:-) BTW issue #2 is now up. This has the file() vs. open() line. Hopefully issue #3 will follow tomorrow or early next week with a line about %*d. > Thanks, anyway. > > -- > David Wild using RISC OS on broadbandwww.davidhwild.me.uk |