Why can't I run this test class?

[Benjamin Kaplan]

On Fri, Sep 11, 2009 at 4:01 AM, Kermit Mei <kermit.mei at gmail.com> wrote:

> On Fri, 2009-09-11 at 00:43 -0700, Chris Rebert wrote:
> > On Fri, Sep 11, 2009 at 12:40 AM, Kermit Mei <kermit.mei at gmail.com>
> wrote:
> > > On Fri, 2009-09-11 at 00:33 -0700, Chris Rebert wrote:
> > >> On Fri, Sep 11, 2009 at 12:30 AM, Kermit Mei <kermit.mei at gmail.com>
> wrote:
> > >> > Dear all,
> > >> >    I'm a newbie for python, and I write a program to test how to
> > >> > implement a class:
> > >> >
> > >> > #!/usr/bin/env
> > >> > python
> > >> >
> > >> > class Test:
> > >> >    'My Test class'
> > >> >    def __init__(self):
> > >> >        self.arg1 = 1
> > >> >
> > >> >    def first(self):
> > >> >        return self.arg1
> > >> >
> > >> > t1 = Test
> > >>
> > >> You missed the parentheses to call the constructor. That line should
> be:
> > >>
> > >> t1 = Test()
> > >>
> > >> Cheers,
> > >> Chris
> > >
> > >
> > > Yes, that can run. But If I put the following code into Test.py :
> > > #!/usr/bin/env python
> |>>>
> > >                                                                    |
> > > class Test:                                                         |
> > >    'My Test class'                                                 |
> > >    def __init__(self):                                             |
> > >        self.arg1 = 1                                               |
> > >                                                                    |
> > >    def first(self):                                                |
> > >        return self.arg1                                            |
> > >                                                                    |
> > >    def setFirst(self,value = 5):                                   |
> > >        self.arg1 = value
> > >
> > > But when I want to run it as a module, something also be wrong:
> > >
> > > $ python
> > > Python 2.6.2 (release26-maint, Apr 19 2009, 01:56:41)
> > > [GCC 4.3.3] on linux2
> > > Type "help", "copyright", "credits" or "license" for more information.
> > >>>> import Test
> > >>>> t1 = Test()
> > > Traceback (most recent call last):
> > >  File "<stdin>", line 1, in <module>
> > > TypeError: 'module' object is not callable
> >
> > You've imported the module `Test`, whose name is determined by the
> > filename (Test.py).
> > To access the class of the same name (`Test`) that is defined in the
> > module, you need to use the dot operator:
> >
> > >>>> import Test
> > >>>> t1 = Test.Test()
> >
> > You should probably use different names for the module/file and the
> > class to avoid confusion.
> > Unlike Java, Python does not observe a direct correspondence between
> > filenames and classes.
> >
> > Cheers,
> > Chris
> > --
>
> Oh, yep!
> Thanks, Cheers.
>
> Can you tell me how can I write __init__.py for modules:
>
> I have a directory like this:
> $ tree
> .
> `-- main
>    |-- MyTestModules
>    |   |-- Test1.py
>    |   `-- Test2.py
>    `-- main.py
>
> 2 directories, 3 files
>
>
> In main.py, I want to run the following code:
>
> #!/usr/bin/env python
>
> import MyTestModules
>
> t1 = Test1()
> t2 = Test2()
>
> print t1.first()
> print t2.first()
>
> ###################################
> The classes Test1 and Test2 just be similar with the Test that I showed
> before. To run main.py correct, how can I orgnize the code under
> directory MyTestModules. (May need a __init__.py file under
> MyTestModules, but I don't know how to write it)
>
>
> Thank you,very much!
> Regards
> Kermit
>
>
Just make a blank file called __init__.py in MyTestModules. That's all you
need. Then, in main.py, you need to either do

import MyImportModules.Test1
t1 = MyImportModules.Test1.Test1()

or

from MyImportModules.Test1 import Test1
t1 = Test1()

Unlike C++ and Java, an import in Python does not make the other module's
stuff available in the local namespace. You only have the one extra name
(the name of the module) and everything else is stored in there. If you want
to add the new module's stuff to the local namespace, you have to do the
"from ... import ...". This is also why you shouldn't make a separate file
for every class. You could put both Test1 and Test2 into a file called
test.py (module names in Python are usually lowercase) and then do "from
MyImportModules.test import Test1, Test2"

>
>
>
>
> --
> http://mail.python.org/mailman/listinfo/python-list
>
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