Chris Hare wrote:
I am having a problem getting around this variable namespace thing.
Consider these code bits
File a.py
from Tkinter import *
import a1
def doAgain():
x =1.Net()
x.show("Again!")
root =k()
root.title("test")
f =rame(root,bg="Yellow")
l =utton(root,text="window 1",command=doAgain)
f.grid()
l.grid()
a =
x =1.Net()
x.show("window 2")
if __name__ ="__main__":
root.mainloop()
File a1.py
from Tkinter import *
class Net:
def __init__(self):
self.window =oplevel()
def show(self,t):
self.l =abel(self.window,text=t)
self.l.grid()
button =utton(self.window, text="Again")
button.bind("<Button-1>", self.Again)
button2 =utton(self.window, text="Dismiss")
button2.bind("<Button-1>", self.hide)
button.grid()
button2.grid()
def Again(self,event):
x =et()
x.show(a)
def hide(self,event):
self.window.destroy()
When I run a.py, it imports a1.py and click on the Again button, I get the error
Exception in Tkinter callback
Traceback (most recent call last):
File
"/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/lib-tk/Tkinter.py",
line 1410, in __call__
return self.func(*args)
File "/Volumes/Development/py/a1.py", line 17, in Again
x.show(a)
NameError: global name 'a' is not defined
I believe this is the expected behavior. so my question is this -- how do I
tell the code in a1.py about the variable a, which exists in a.py? Do I have
to pass it as part of the function call, or what? using
global a
in a1.py doesn't change anything.
since I am using SQLite for the disk database, I was thinking I could keep all the
"global" variables in an in memory database and just access them when I need
to, but other ideas are welcome.
Thanks,
Chris
First rule is never have circular referencing between modules. In other
words, since a.py imports a1.py, a.py can refer to things in a1.py, but
never the other way around. Any time you need to look backwards, find
another means.
One approach is to create another module c.py as a container to hold
those things that both a and a1 need. That way they both import c, and
there's no problem.
Another approach is to pass the global from a.py into a1.py, and use it
that way.
And since you only have these two modules, you could just define it in
a1.py, and reference it from a.py as
a1.a
I would point out that using the same name for a module and a global
variable is bad practice. it certainly makes it hard to describe in
this case.
HTH,
DaveA
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