Re: eval, exec and execfile dilemma

Chris Angelico wrote:
On Sat, Jul 30, 2011 at 8:48 PM, Laszlo Nagy <gandalf@xxxxxxxxxxxx> wrote:
the exec statement can be used to execute a def statement. However, I see no
way to change the globals, so I cannot use the exec statement.

A quick test in Python 2.4.5:
exec "def foo():\n\tbar+=1\n\treturn 1\n"
bar=2
foo()
Traceback (most recent call last):
File "<stdin>", line 1, in ?
File "<string>", line 2, in foo
UnboundLocalError: local variable 'bar' referenced before assignment

This works, though (at least it does on 2.7):

--> exec "def foo():\n\tglobal bar\n\tbar+=1\n\treturn 1\n"
--> bar = 9
--> foo()
1
--> bar
10

Laszlo, why do you think you can't use exec?

~Ethan~
.

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