Bug in Python class static variable?

[Bruza]

I am trying to define a class static variable. But the value of the
static variable seems to be only defined inside the file that the
class is declared. See the code below. When I run "python w.py", I
got:

000=======Hello World
001=======Hello World
002=======Not Initialized
003=======Not Initialized
004=======Not Initialized
005=======Hello World

Looks like even though the class variable "ClassW.w_classStaticVar"
was set inside "startup()", the value never carried over to functions
in "a.py". Is this a bug in Python's static variable handling. I am
running Python 2.4.4.
Ben
#===== file: w.py ========
from a import *

class ClassW:
w_classStaticVar = "Not Initialized"

def initA(self):
print "001=======>", ClassW.w_classStaticVar
obj = ClassA()
obj.init2()
print "005=======>", ClassW.w_classStaticVar

def startup():
ClassW.w_classStaticVar = "Hello World"
wo = ClassW()
print "000=======>", ClassW.w_classStaticVar
wo.initA()

if __name__ == '__main__':
startup()

#===== file: a.py ========
from w import *

class ClassA:
def __init__(self):
print "002=======>", ClassW.w_classStaticVar

def init2(self):
print "003=======>", ClassW.w_classStaticVar
w = ClassW()
print "004=======>", ClassW.w_classStaticVar

[Duncan Booth]

Bruza <be*****@gmail.comwrote:

I am trying to define a class static variable. But the value of the
static variable seems to be only defined inside the file that the
class is declared. See the code below. When I run "python w.py", I
got:

When you run "python w.py" the *script* w.py is loaded as the module
__main__. Importing a module called 'w' creates a new module which is
unrelated to __main__. If you want access to variables defined in the main
script then you need to import __main__.

Don't use 'from module import *':

The import statements are executed when the interpreter reaches them in the
source. Even if you fix your code to import from __main__, the values you
try to import from __main__ won't exist when the import statement executes:
the first 'from a import *' will load and execute all of module 'a', but
when that executes 'from __main__ import *' it just imports names defined
in the main script *before* a was imported.

In general, don't try to do this: put all your classes into modules and
just put minimal startup code into a script.

[Bruza]

On Jul 2, 3:52 am, Duncan Booth <[e-mail]:

Bruza <[e-mail]:

I am trying to define a class static variable. But the value of the
static variable seems to be only defined inside the file that the
class is declared. See the code below. When I run "python w.py", I
got:

When you run "python w.py" the *script* w.py is loaded as the module
__main__. Importing a module called 'w' creates a new module which is
unrelated to __main__. If you want access to variables defined in the main
script then you need to import __main__.

Don't use 'from module import *':

The import statements are executed when the interpreter reaches them in the
source. Even if you fix your code to import from __main__, the values you
try to import from __main__ won't exist when the import statement executes:
the first 'from a import *' will load and execute all of module 'a', but
when that executes 'from __main__ import *' it just imports names defined
in the main script *before* a was imported.

In general, don't try to do this: put all your classes into modules and
just put minimal startup code into a script.

Duncan,

Thanks for replying. However, I am still confused...
Even if I put "from __main__ import *" in both "a.py" and "w.py", I
still got
the same results. So, how should I re-structure my program to make the
class
static variable works???

Thanks,

Ben