Skip, I think you have misunderstood the point I was making. It was not whether the loop variable should leak out of a list comprehension. Rather, it was whether a local variable should, so to speak, "leak into" a list comprehension. And the answer is: it depends on whether the code is executed normally, or via exec/eval. Example:
def Test(): x = 1 print([x+i for i in range(1,3)]) # Prints [2,3] exec('print([x+i for i in range(1,3)])') # Raises NameError (x) Test()
I (at least at first) found the difference in behaviour surprising.
On 08/06/2018 19:27, Skip Montanaro wrote:
Is this a bug or a feature?
The bug was me being so excited about the new construct (I pushed in someone else's work, can't recall who now, maybe Fredrik Lundh?) that I didn't consider that leaking the loop variable out of the list comprehension was a bad idea. Think of the Py3 behavior as one of those "corrections" to things which were "got wrong" in Python 1 or 2. :-)
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