On 14 Oct 2005 12:11:58 -0700, "PyPK" <[EMAIL PROTECTED]> wrote:
>Hi if I have a function called
>tmp=0
>def execute():
> tmp = tmp+1
> return tmp
>
>also I have
>def func1():
> execute()
> ....
>and
>def func2():
> execute()
> ....
>
>now I want execute() function to get executed only once. That is the
>first time it is accessed.
>so taht when funcc2 access the execute fn it should have same values as
>when it is called from func1.
>
You could have the execute function replace itself with a function
that returns the first result from there on, e.g., (assuming you want
the global tmp incremented once (which has bad code smell, but can be expedient
;-)):
>>> tmp = 0
>>> def execute():
... global tmp, execute
... tmp = cellvar = tmp + 1
... def execute():
... return cellvar
... return tmp
...
>>> def func1():
... return execute() # so we can see it
...
>>> def func2():
... return execute() # so we can see it
...
>>> func1()
1
>>> tmp
1
>>> func2()
1
>>> tmp
1
>>> execute()
1
>>> execute
<function execute at 0x02EF702C>
>>> import dis
>>> dis.dis(execute)
5 0 LOAD_DEREF 0 (cellvar)
3 RETURN_VALUE
But if you want to call the _same_ "execute" callable that remembers that
it's been called and does what you want, you need a callable that can
remember state one way or another. A callable could be a function with
a mutable closure variable or possibly a function attribute as shown in
other posts in the thread, or maybe a class bound method or class method,
or even an abused metaclass or decorator, but I don't really understand
what you're trying to do, so no approach is likely to hit the mark very well
unless you show more of your cards ;-)
Regards,
Bengt Richter
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