python中的全局变量Scope

Question

Should I need to Global everything Global? Considering scope?

I keep randomly running into this problem, Im gonna assume its some how a syntax problem on myside. But variables out side of a scope in python seems to be inconsistent... my situation is

libFound=False

def Setup():
   _setup_import()
   print('booting:',libFound)
   #--Here I get False?
   if libFound:
      _boot()
   else:print('Did not Boot')

def _setup_import():
   sys.path.append(PATH)
try:
   import libwrapper
   global libwrapper
except:
   #Critical Exception
else:
   #found
   libFound=True
   print(libFound)#--Here I get True

I assume this is garbage collection but I would think it would match gloval before local variables, should I have to global everything global? Scope is scope, I seem to get this often in python. I would like to include it seems to happen most when initiateing with None or it being Bool

Makeing variables global,checking syntax, I've tried researching this but I don't understand if its my syntax possibly or my lack or understanding of how python is actually handleing variable

Answer 1

A global variable is, by definition, bound in the global scope. But assignments to names in a function always define a new local variable, unless you declare the name as global or non-local using global or nonlocal, respectively. – chepner 10 mins ago Boom... inside the scope of _setup_libraries() I made it global and it worked, like you said inside the scope of the method it was local

Answer 2

This has nothing to do with the garbage collector. I think you may misunderstand how scoping works in python.

See code & comments in it below. I hope it helps.

myGlobal = False

def ask_global():
    # To use Glboal Variable, we dont need to use global keyword
    print(myGlobal)

def toggle_global():
    # Changes the value of the global variable
    global myGlobal
    myGlobal = not myGlobal

def global_false():
    # Will not actually set myGlobal false, because scoping
    # When assigning a global without first declaring it as global, 
    # it will be a new local variable
    # myGlobal = not myGlobal
    # would result in 'myGlobal' referenced before assignment
    myGlobal = False
    

print(myGlobal) # False
ask_global() # False
if True:
    # We're in global scope here, changing the global variable
    myGlobal = True

print(myGlobal) # True
ask_global() # True

global_false()
print(myGlobal) # True
ask_global() # True

toggle_global()
print(myGlobal) # False
ask_global() # False