Python / using modules in class methods

introuble · 01-04-2007, 02:36 PM

Ok.. check out the following some-what-pseudocode:

Code:

class introuble:
    def do_something(self):
        import some_module
        some_module.some_function()

    def do_something_else(self):
        import some_module
        some_module.some_function_2()

The thing is.. I'd like *not* to import "import some_module" within each method.. but rather import it only once. Is this possible?

introuble · 01-04-2007, 02:42 PM

Figured it out just a couple of seconds after this post

Code:

class introuble:
    import some_module
    def do_something(self):
        self.some_module.some_function()

Dan04 · 01-04-2007, 07:24 PM

A module only gets imported once regardless of how many times "import some_module" gets executed. So, except for stylistic reasons, there's really no need to rewrite it.

billiejoex · 01-16-2007, 10:00 AM

In python exists "namespaces". If you import a certain module inside a class/function it will only be available in the class/function namespace:

Code:

>>> def fun():
...     import os
...
>>> fun()
>>> os
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
NameError: name 'os' is not defined
>>>

Otherwise, if you import module in the 'global' namespace it will available for any class/module of your script:

Code:

>>> import os
>>> def fun():
...     os
...
>>> os
<module 'os' from 'C:\Python24\lib\os.pyc'>
>>> fun()
>>>