On 7/17/2009 7:34 AM Jean-Michel Pichavant said...
Steven D'Aprano wrote:
On Thu, 16 Jul 2009 15:53:45 +0200, Jean-Michel Pichavant wrote:
Given three result codes, where 0 means "no error" and an arbitrary non-
zero integer means some error, it is simple and easy to write:
failed = result_1 or result_2 or result_3
The equivalent:
failed = (result_1 != 0) or (result_2 != 0) or (result_3 != 0)
# or if you prefer:
succeeded = (result_1 == 0) and (result_2 == 0) and (result_3 == 0)
[snip]
This is, I guess, where we disagree. I find the second proposal less
error prone, and universally understandable unlike the first one. It may
be verbose, it may look even lame to some people, but in the end this is
perfectly reliable, because you manipulate only False or True within the
boolean operations.
The first form does not clearly show what is the failed criteria. It
just happens by coincidence
No -- it happens by design because the premise is 'where 0 means "no
error" and an arbitrary non-zero integer means some error'.
that in this case the failed criteria
matches the Nothingness of result_1, result_2, result_3. What if results
may be 'OK' or 'KO'.
Which by definition won't happen for the example cited...
failed = result_1 or result_2 or result_3
won't work.
... so you certainly wouldn't write a test that couldn't properly
determine success or failure.
failed = (result_1 =='KO') or (result_2 =='KO') or (result_3 =='KO') is
lame but reliable.
In this case I'd write something that meets the specs of the problem
your addressing...
failed = 'KO' in (result_1,result_2,result_3)
Emile
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