Moving from Python 2 to Python 3: A 4 page "cheat sheet"

[Lie Ryan]

On 12/2/2009 1:03 AM, Mark Summerfield wrote:
> 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 uses Python 3.1 syntax since that looks like being the standard for
> a few years in view of the language moratorium.
>
> The document is U.S. Letter size but will also print fine on A4
> printers.
>
> It is available as a free PDF download (no registration or anything)
> from InformIT's website. Here's the direct link:
> http://ptgmedia.pearsoncmg.com/imprint_downloads/informit/promotions/python/python2python3.pdf
>
> And of course, if you want more on Python 3, there's always the
> documentation---or my book:-)
> "Programming in Python 3 (Second Edition)" ISBN-10: 0321680561.

Nice.

I suggest changing the lambda example a bit, the current example says:
Python 2                      Python 3
lambda (a,b): a + b           lambda t: t[0] + t[1]
                               lambda a, b: a + b

into something like:

Python 2                      Python 3
lambda (a,b),c: a + b + c     lambda t, c: t[0] + t[1] + c
                               lambda a, b, c: a + b + c

it is unclear at first sight that it refers to tuple argument unpacking. 
There should also some mention that tuple argument unpacking for regular 
function (def) is also gone.



Also, I'm not sure what this change is referring to:
Python 2                 Python 3
L = list(seq)            L = sorted(seq)
L.sort()

L.sort is still available in python, and sorted() have been available 
since python 2. Both list.sort() and sorted() are for different purpose, 
and neither will be deprecated. What's the change here?