[Tutor] Globals?

[Kent Johnson]

Liam,

When you make any assignment to a variable inside a function, Python 
assumes that the variable is local to the function. Then any use of the 
variable before it's first assignment is an error.

To force a variable in a function to be global, put a 'global' statement 
in the function. You need to add
   global badConnectCycle
to your function getReturns

If you don't make any assignment to a variable, then the global (module) 
namespace is searched. That is why badUserList works fine - you never 
assign it, you just access the list methods.

Kent

Liam Clarke wrote:
> Hi all, 
> 
> Having trouble with something, it is 3:30am in the morning, so this
> may be a dumb problem, if so, I apologise.
> 
> In my prog, there's two variables created right at the get go -
> 
> import imaplib
> import email.Parser
> import os
> import os.path
> import datetime
> import md5
> from pause import *
> 
> badUserList=[]
> badConnectCycle=0
> 
> as I want them to be global within this module, so that another module
> can pick them out easily.
> 
> Now, I just added badConnectCycle, badUserList has been there awhile,
> and it's used in
> 
> the function connectToImap which is called by getReturns which is
> called by main(), and my other module can get it no problem, so
> badUserList is fine.
> 
> badConnectCycle... is giving me errors -
> 
> badConnectCycle is used in getReturns, as so - 
> 
> if session == "NoConnect" : 
>             badConnectCycle += 1
>             continue
> 
> 
> function getReturns ends as follows - 
> 
> if badConnectCycle == len(user) and badConnectCycle > 0: return ("NoConnect","")
> if badUserList and not sender: return ('NoLogin',"")
> if matchindex[0] and not sender: return ('NoNew', '')
> if not sender: return ("NoMatch","")
> return (sender, msgdata)
> 
> and it's at that line
> 
>  if badConnectCycle == len(user) and badConnectCycle > 0:
> 
> that I get this error:
> 
> UnboundLocalError: local variable 'badConnectCycle' referenced before
> assignment.
> 
> Which is confusing me because badUserList is used within a function
> called by getReturns, and I've had no problem with it.
> 
> Help anyone? Much appreciated if you can.
> 
> Regards,
> 
> Liam Clarke