Thank you Steven,
The funny thing is that I have taken a look at wikipedia just before to be
sure that I wasn't wrong :D
I agree with you about not making a clear function to just put what I've put
in my sample, but
this sample was more simple that what I really need for explaining purpose.
In reality My clear function is cleaning a dozen of arrays and since I need
to call it several time I have made a function of it.
a few days ago I was trying python for the little script I'm working on and
this language is more powerfull that I was thinking and very pleasant to
code.
I believe I will use it more in the future.
Dominique.
"Steven Bethard" <[EMAIL PROTECTED]> a �crit dans le message de news:
[EMAIL PROTECTED]
> houbahop wrote:
>> Hello again everyone ,
>> var2[:]=[] has solved my problem, and I don't understand why it is
>> programming by side effect.
>> I don't think it's bad, look at this, it's what I've done :
>>
>> def Clear(lvar)
>> lvar[:]=[]
>>
>> def main (starting class)
>> var1=[]
>> var1.append('a')
>> Clear(var1)
>
> From http://en.wikipedia.org/wiki/Side-effect_(computer_science)
>
> In computer science, a side-effect is a property of a programming language
> function that it modifies some state other than its return value.
>
> Given this definition, I think you're fine -- clearing the list isn't a
> side effect of the function; it is the purpose of the function. Hence the
> function has no return value.[1]
>
>
>
> Of course, in this simple case, I wouldn't be likely to write the clear
> function since the inline code is simpler and has less overhead:
>
> def main()
> var1 = []
> var1.append('a')
> var1[:] = []
>
> or, since in this case, you only care about var1, you can just rebind it
> (and let Python garbage-collect the old list):
>
> def main()
> var1 = []
> var1.append('a')
> var1 = []
>
> Steve
>
> [1] Technically, all Python functions without a return statement return
> None, but for our purposes, we can consider a function like this to have
> "no return value".
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