On Wed, Mar 25, 2015 at 1:29 PM, Manuel Graune <manuel.gra...@koeln.de> wrote:
> Hi,
>
> I'm looking for a way to supply a condition to an if-statement inside a
> function body when calling the function. I can sort of get what I want
> with using eval (see code below) but I would like to achieve this in a
> safer way. If there is a solution which is safer while being
> less flexible, that would be fine. Also, supplying the condition as a
> string is not necessary. What I want to do is basically like this:
>
> def test1(a, b, condition="True"):
> for i,j in zip(a,b):
> c=i+j
> if eval(condition):
> print("Foo")
>
I'm not sure I understand your question, but condition will evaluate
to True or False regardless, so:
if condition:
print ("Foo")
else:
print ("Bar")
eval can be dangerous as someone could put some unknown command with
side effects in condition
> test1([0,1,2,3],[1,2,3,4],"i+j >4")
> print("Bar")
> test1([0,1,2,3],[1,2,3,4],"c >4")
> print("Bar")
> test1([0,1,2,3],[1,2,3,4],"a[i] >2")
> print("Bar")
> test1([0,1,2,3],[1,2,3,4])
>
> Resulting in
>
> Foo
> Foo
> Bar
> Foo
> Foo
> Bar
> Foo
> Bar
> Foo
> Foo
> Foo
> Foo
>
> Thanks for your help
>
> Regards,
>
> Manuel
>
> --
> A hundred men did the rational thing. The sum of those rational choices was
> called panic. Neal Stephenson -- System of the world
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--
Joel Goldstick
http://joelgoldstick.com
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