Scope (?) question

[Inyeol Lee]

On Jun 15, 3:22 pm, Peter <peter.milli... at gmail.com> wrote:
> I am puzzled by what appears to be a scope issue - obviously I have
> something wrong :-)
>
> Why does this work:
>
> if __name__ == 'main':
>   execfile('test-data.py')
>   print data
>
> and yet this doesn't (I get "NameError: global name 'data' not
> defined"):
>
> def X():
>   execfile('test-data.py')
>   print data
>
> where test-data.py is:
>
> data = [1,2,3,4]
>
> I checked help on execfile and could only find the following
> (mystifying) sentence:
>
> "execfile() cannot be used reliably to modify a function’s locals."
>
> Thanks
> Peter

This is due to CPython's static optimization of local name lookup.
Dummy 'exec' statement disables this and makes your example work:

def X():
  exec "None"
  execfile('test-data.py')
  print data

--inyeol