loop scope

Donn Cave donn at drizzle.com
Fri Mar 12 07:34:30 CET 2004


Quoth user at domain.invalid:
| Terry Reedy wrote:
|
|> For loops with a break statement, the value of the loop index when the
|> break occurs may be the answer sought or needed to calculate it.  For list
|> comps which cannot have break, it is an artifact which may disappear in
|> 2.4.
|
| If I understand you, I don't think I like this idea. It 
| adds complexity to the mental model of a loop. "The 
| loop variable disappears when the loop ends unless the 
| loop contains a break".
|
| In my opinion, Python should pick a model and stick to 
| it. Loop variables are either ordinary variables that 
| exist until you explicitly delete them, or they are 
| special variables that automagically disappear at the 
| end of the loop. I vote for the first one.

That makes sense to me, but I read "For list comps" as "For list
comprehensions (but not conventional loops.)"  List comprehensions
shouldn't need to have every side effect of the equivalent loop.

	Donn Cave, donn at drizzle.com



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