modules and namespaces

[Jaime Wyant]

Each module has its own "namespace", which is like a dictionary of
objects that the module can "see".  I use the term dicitionary because
locals() and globals() both return dictionaries -- someone may correct
me on this (or confirm what I say)...

You have local and global variables.

Locals are variables in the scope of a function.

def myfun():
    localvar = 1

`globals' are really 'module' global only.

# mymodule
global_var = 3

def myfun()
    print global_var

    # This is a *gotcha* -- you can't change global variables this way.
    # here, a new local variable global_var is initialized.
    global_var = 3

def changeglobal():
    # you have to use `global' to instruct python to use the `global'
instance of the variable
    # instead of creating a new one when you assign to it.
    global global_var 
    global_var = 3    

You can only see variables you've created or modules you've imported. 
Becase you haven't imported string in m2 or m3, you can't see them.

hth,
jw

On 4/19/05, Mage <mage at mage.hu> wrote:
>        Hello,
> 
> I thought that this will work:
> 
> #m1.py
> def f1():
>     return string.join('a','a')
> 
> #m2.py
> def f2():
>     return string.join('b','b')
> 
> #main.py
> import string
> import m1
> import m2
> 
> print f1()
> print f2()
> 
> ---------
> 
> However it doesn't work until I import the string module into m1 and m2
> modules. I found in the manual that imported modules will be searched in
> the container module first. Is it more efficient to import the string
> module into main and m1 and m2 than importing only into m1 and m2?
> 
>        Mage
> 
> --
> http://mail.python.org/mailman/listinfo/python-list
>