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From: Peter Otten <__peter__@web.de>
Subject: Re: Dynamic variable creation from string
Date: Fri, 09 Dec 2011 12:27:47 +0100
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Xref: x330-a1.tempe.blueboxinc.net comp.lang.python:16908

Massi wrote:

> for k in D : exec "%s = D[k]" %k
> 
> That seems to do the trick, but someone speaks about "dirty code", can
> anyone point me out which problems this can generate?

exec can run arbitrary code, so everybody reading the above has to go back 
to the definition of D to verify that it can only contain "safe" keys. 
Filling D with user-input is right out because a malicious user could do 
anything he likes. Here's a harmless demo that creates a file:

>>> d = {"x = 42\nwith open('tmp.txt', 'w') as f:\n f.write('whatever')\nx": 
123}
>>> for k in d: exec "%s = d[k]" % k
...
>>> x
123
>>> open("tmp.txt").read()
'whatever'