Edward Cherlin schrieb:
On Sun, Apr 19, 2009 at 12:07 PM, Laura Creighton <l...@openend.se> wrote:
One note:
It is very important to teach your students how to read code. ...
...
It would be interesting to go through this collection of examples
used in teaching 2.x, and find out how much of the new code just
works, and what are the remaining issues
It's certainly not the only issue, if code 'just works' or not. There
are quite a few
differences between Python 2 and Python 3 that concern the semantics of
code.
As a very elementary example consider the different meaning of
range(5)
in Python 2/3. Imho in this case at first it would be important to find
didactically clean ways to explain new concepts like these to beginners.
Of course I know that these concepts are not entirely new, but with
Python 3 they need to appear at a much earlier stage, e. g. when
introducing the for loop.
In 'former times' we could say: range(5) is a list (i. e. a container or
a compound
data type) and the for loop does things for every element in this list.
And you could view
this list:
range(5)
[0, 1, 2, 3, 4]
for item in range(5):
print item
0
1
2
3
4
type(range(5))
<type 'list'>
... easily to grasp
Now, with Python 3, we have:
range(5)
range(0, 5)
for item in range(5):
print(item)
0
1
2
3
4
type(range(5))
<class 'range'>
How do you explain the nature of range to beginners? (Not a a rhetorical
question, I'd really like to know different approaches how to do it!)
At least you can see, that this is a much more important question
than e. g. the parentheses around item (because of print being a
function now - but even here the semantic difference between a
function and a statement is the point and not the parentheses ...)
Regards,
Gregor
_______________________________________________
Edu-sig mailing list
Edu-sig@python.org
http://mail.python.org/mailman/listinfo/edu-sig
