[python-win32] How Can I exec() a statement?
steve at holdenweb.com
Wed Apr 6 20:55:10 CEST 2005
* William wrote:
> Hello all.
> Thanks for the tips and solutions posted to the list so far. This is a
> general python question, not windows specific. It is my turn to ask.
> (Perhaps the notion below will suggest some development to one of you.
> Who knows?)
> I want to execute a statement indirectly in Python. Take the simple case
> below. The chevrons ">> " indicate the result of the statement
> b = 2
> a = b + 6
> eval('a = b + 6', globals(), locals() )
> >> File "not_much_at_all.py", line 21, in ?
> >> rslt = eval('a = b + 6', globals(), locals() )
> >> File "<string>", line 1
> >> a = b + 6
> >> ^
> >> SyntaxError: invalid syntax
> While I appreciate that "eval()" is not the way to do this, it is also
> true that "eval()" accurately signals my intention in this sample.
> HOW -- or, is it possible -- to execute the an assignment statement from
> a string?
> I have used compile() and considered using a 'block'. Compile doesn't
> help. And I can't find an equivalent for 'eval( <block> )' ...
> Who has the answer?
Well, you do! You ask how to exec a statement, and the answer is ... use
an "exec" statement!
>>> exec "a = 25/3"
Steve Holden +1 703 861 4237 +1 800 494 3119
Holden Web LLC http://www.holdenweb.com/
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