Use cases for del

Ron Adam rrr at ronadam.com
Sun Jul 10 13:59:46 EDT 2005


Reinhold Birkenfeld wrote:
> Ron Adam wrote:
> 
> 
>>>    >>> 'abc' is 'abcd'[:3]
>>>    False
>>
>>Well of course it will be false... your testing two different strings! 
>>And the resulting slice creates a third.
>>
>>Try:
>>
>>ABC = 'abc'
>>
>>value = ABC
>>if value is ABC:   # Test if it is the same object
>>    pass
> 
> 
> That's not going to buy you any time above the "is None", because identity-
> testing has nothing to do with the type of the object.

Ok, I retested it... Not sure why I was coming up with a small 
difference before.  <shrug>  It seemed strange to me at the time which 
is part of why I asked.

My point was using strings "could" work in same context as None,  (if 
None acted as del), with out a performance penalty.  Anyway, this is all 
moot as it's an solution to a hypothetical situation that is not a good 
idea.

> Additionally, using "is" with immutable objects is horrible.

Why is it "horrible"?  Oh nevermind.  ;-)


Cheers,
Ron


> Reinhold



More information about the Python-list mailing list