[Python-Dev] Python3 compiled listcomp can't see local var (original) (raw)

Eric Fahlgren ericfahlgren at gmail.com
Mon Jun 11 18:31:03 EDT 2018


On Mon, Jun 11, 2018 at 3:10 PM Rob Cliffe via Python-Dev < python-dev at python.org> wrote:

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.

​Change 'def' to 'class' and run it again. You'll be even more surprised.​ -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://mail.python.org/pipermail/python-dev/attachments/20180611/0934b1d2/attachment.html>



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