In <[EMAIL PROTECTED]> Larry Bates <[EMAIL PROTECTED]> writes:
>kj wrote:
>> Yet another noob question...
>>
>> Is there a way to mimic C's static variables in Python? Or something
>> like it? The idea is to equip a given function with a set of
>> constants that belong only to it, so as not to clutter the global
>> namespace with variables that are not needed elsewhere.
>>
>> For example, in Perl one can define a function foo like this
>>
>> *foo = do {
>> my $x = expensive_call();
>> sub {
>> return do_stuff_with( $x, @_ );
>> }
>> };
>>
>> In this case, foo is defined by assigning to it a closure that has
>> an associated variable, $x, in its scope.
>>
>> Is there an equivalent in Python?
>>
>> Thanks!
>>
>> kynn
>First names in Python are just that, names that point to objects. Those
>objects
>can contain any type of information including other objects. They are NOT
>buckets where things are stored.
>1) Names (variables in Perl/C) defined within a Python function are placed in
>its local namespace. They are not visible in the global namespace.
>2) Yes you can have a local name point to a global. This is often used in
>classes with attributes because looking up local is somewhat quicker than
>looking up the class attribute.
>def foo():
> x = expensive_call
> return do_stuff_with(x())
Maybe I'm missing your point, the goal is to have a "runtime
constant" associated with the function. In the your definition of
foo, expensive_call gets called every time that foo gets called;
this is what I'm trying to avoid!
Maybe it's easier to see what I mean with JavaScript:
function foo() {
if (foo.x === undefined) foo.x = expensive_call();
return do_stuff_with(foo.x);
}
Here, expensive_call is called only once (assuming it never returns
undefined).
OK, I guess that in Python the only way to do what I want to do is
with objects...
kynn
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