Newcomer struggling with tutorial

Andrew Koenig ark at acm.org
Sun Oct 5 12:25:02 EDT 2003


CPK> "Tim Peters" <tim.one at comcast.net> wrote in
CPK> news:mailman.1065325869.29360.python-list at python.org: 

>> Perhaps that's confusing you.).

CPK> Yes. I screwed up with my example and I'm sorry to waste people's time. I 
CPK> was getting confused.

CPK> What I found so disturbing is that

CPK> a < b == c

CPK> is not equivalent either to

CPK> (a < b) == c

CPK> nor to

CPK> a < (b == c)

CPK> since (given that for example (a, b, c) == (-1, 77, 1)) the first
CPK> is false while the latter are both true.

Right.

        a < b == c

is equivalent to

        (a < b) and (b == c)

except that b is evaluated only once in the first example.  This behavior
is most useful when both relations are of the same kind, such as

        if 0 <= n < 10:
                # ...

-- 
Andrew Koenig, ark at acm.org




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