python loops

Steve Holden steve at holdenweb.com
Sun Sep 3 13:55:20 CEST 2006


Nicko wrote:
> Fredrik Lundh wrote:
> 
>>Nicko wrote:
>>
>>
>>>... In the case of the idiom "for i in
>>>range(x):..." there absolutely no utility whatsoever in creating and
>>>recording the list of objects.
>>
>>for short lists, both objects create the *same* number of objects.
> 
> 
> This is true for long lists too, if you iterate over the full range,
> but what I wrote was "creating and recording". The range() function
> generates a variable-sized, potentially large object and retains all of
> the items in the range while xrange() generates a fairly small, fixed
> sized object and only hangs on to one item at a time.  Furthermore,
> it's not at all uncommon for loops to be terminated early. With range()
> you incur the cost of creating all the objects, and a list large enough
> to hold them, irrespective of if you are going to use them.
> 
> 
>>if you cannot refrain from pulling arguments out of your ass, you not
>>really the right person to talk about hygiene.
> 
> 
> I'm impressed but your mature argument. Clearly, in the face of such
> compelling reasoning, I shall have to concede that we should all
> generate our range lists up front.
> 
I'm impressed that you think any of this will be news to the effbot, 
whose sagacity is exceeded only by his irritability in the face of 
ignorance.

regards
  Steve
-- 
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