# Your impression of for-novice writings on assertions

Raymond Hettinger python at rcn.com
Tue Feb 2 22:22:55 CET 2010

On Feb 2, 12:54 pm, "Alf P. Steinbach" <al... at start.no> 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

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
+b*b==c*c.

Raymond