[Tutor] Help with Guess the number script

[eryksun]

On Sat, Mar 8, 2014 at 8:36 AM, Dave Angel <davea at davea.name> wrote:
>  Mark Lawrence <breamoreboy at yahoo.co.uk> Wrote in message:
>> On 08/03/2014 01:23, Scott W Dunning wrote:
>>
>>> def print_hints(secret, guess):
>>>      if guess < 1 or guess > 100:
>>
>> Only now do I feel that it's time to point out that the above line would
>> probably be written by an experienced Python programmer as:-
>>
>> if 1 > guess > 100:
>>
>
> With an appropriate 'not' or its equivalent,  of course.

i.e.

    guess < 1 or guess > 100

becomes

    not not (guess < 1 or guess > 100)

distribute over the disjunction

    not (not (guess < 1) and not (guess > 100))

logically negate the comparisons

    not (1 <= guess and guess <= 100)

finally, write the conjoined comparisons as a chained comparison:

    not (1 <= guess <= 100)

i.e., guess isn't in the closed interval [1, 100].

Anyway, you needn't go out of your way to rewrite the expression using
a chained comparison. The disjunctive expression is actually
implemented more efficiently by CPython's compiler, which you can
verify using the dis module to disassemble the bytecode.