[Tutor] check_range

[Juan Shen]

I agree with Kent's opinion.  A boolean statement, like 9<value<90,
should be somelike a basic statement, which needn't be commented.
However, if it is written as 

>>> ( 9 < value ) and ( value < 90 )

, maybe a good sense of boolean type will be made, because 'and'
operation is always associating with boolean.

	Juan Shen
	

ÔÚ 2004-12-15ÈýµÄ 07:43 -0500£¬Kent JohnsonдµÀ£º
> Brian van den Broek wrote:
> > DogWalker said unto the world upon 2004-12-15 00:32:
> > 
> >> "Brian van den Broek" <bvande at po-box.mcgill.ca> said:
> >>> I have a some style suggestions for you, too.
> >>>
> >>> Try it this way:
> >>>
> >>> def check_in_range(value):
> >>>        in_range = False
> >>>        if 9 < value < 90:
> >>>            in_range = True
> >>>        return in_range
> >>
> >> Shorter:
> >>     def check_in_range(value):
> >>         return 9 < value < 90
> > 
> > 
> > Indeed. Good one. I never seem to think of such very direct ways, but 
> > there you have it. It might say more about my psychology than anything 
> > else, but I think I'd be tempted to put a brief comment on that code. 
> > (Such as # returns True if the test, False otherwise.) My guess is that 
> > if I had to read it more than twice, the time spent writing the comment 
> > would be more than regained in spending less time scratching my head. 
> > This might also be a matter of little experience, too.
> 
> Of course put a comment if you like, but this is very concise, idiomatic code and I hope you will 
> get used to it so the comment is not needed.
> 
> The value of the expression '9 < value < 90' is actually a boolean True or False, so testing the 
> expression and explicitly returning True or False is redundant. You are using four lines of code to 
> do the work of one.
> 
> In general, Python's flexibility with boolean values is a strength of the language and I recommend 
> you try to get comfortable with it.
> 
> > 
> > At any rate, I certainly would agree that yours is bound to be better in 
> > any situation where speed of execution mattered a lot.
> 
> Or readability, IMO.
> 
> Kent
> 
> > 
> > Best,
> > 
> > Brian vdB
> > 
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