Question

I have two files, one is in the webroot, and another is a bootstrap located one folder above the web root (this is CGI programming by the way).

The index file in the web root imports the bootstrap and assigns a variable to it, then calls a a function to initialize the application. Everything up to here works as expected.

Now, in the bootstrap file I can print the variable, but when I try to assign a value to the variable an error is thrown. If you take away the assignment statement no errors are thrown.

I’m really curious about how the scoping works in this situation. I can print the variable, but I can’t asign to it. This is on Python 3.

index.py

# Import modules import sys import cgitb;  # Enable error reporting cgitb.enable() #cgitb.enable(display=0, logdir='/tmp')  # Add the application root to the include path sys.path.append('path')  # Include the bootstrap import bootstrap  bootstrap.VAR = 'testVar'  bootstrap.initialize() 

bootstrap.py

def initialize():     print('Content-type: text/html\n\n')     print(VAR)     VAR = 'h'     print(VAR) 

Thanks.

Edit: The error message

UnboundLocalError: local variable 'VAR' referenced before assignment        args = ('local variable 'VAR' referenced before assignment',)        with_traceback = <built-in method with_traceback of UnboundLocalError object at 0x00C6ACC0> 

Answer 1

try this:

  def initialize():     global VAR     print('Content-type: text/html\n\n')     print(VAR)     VAR = 'h'     print(VAR)  

Without ‘global VAR’ python want to use local variable VAR and give you ‘UnboundLocalError: local variable ‘VAR’ referenced before assignment’