From: Raymond Hettinger on
On Feb 2, 12:54 pm, "Alf P. Steinbach" <al...(a)> wrote:
> The first topic is about assertions and exceptions. I wonder whether this text
> is easy or difficult to understand for a beginner. Or any improvements that
> could be made.

To my eyes it reads nicely. You may want to try it out on a real
beginner to get their feedback.

I like your section on assertions. You could add examples of other
ways assertions can be used (loop invariants, sanity checks, post-
condition contract checks). For example, validate a loop invariant
during a selection sort. In the hypot() example, use an assertion for
sanity checking by verifying an expected mathematical relationship
such as the triangle inequality: assert abs(c) <= abs(a) + abs(b).
The pythagorean triple example can use assertions to check post
conditions: assert all(isinstance(x, int) for x in (a,b,c)) and a*a


From: Irmen de Jong on
On 2-2-2010 21:54, Alf P. Steinbach wrote:
> I've started on ch 3 of my beginner's intro to programming, now delving
> into the details of the Python language.

I think it's a good read so far. I just don't like the smilies that
occur in the text. It's a book (or article) that I'm reading, not an
instant messaging conversation.