[Tutor] How to use a module when only import package

[leechau]

I wrote module1 in package1, and want to use a method named 'method1' in
module1, the caller(test.py) is like this:

import package1
package1.module1.method1()

module1.py is like this:

def method1():
print 'method1 run!'

The filesystem structure is:
test.py
package1
  |__ __init__.py
  |__ module1.py

When i run test.py, the output is:
AttributeError: 'module' object has no attribute 'module1'
File "e:\MyDoc\GODU_BVT\test.py", line 2, in 
  package1.module1.method1()

If test.py is modified to:
import package1.module1
...
then everything goes well. Python documentation said:
"Contrarily, when using syntax like import item.subitem.subsubitem, each
item except for the last must be a package; the last item can be a
module or a package but can’t be a class or function or variable defined
in the previous item."

Obviously we can import a package besides a module, so i don't know why
the "import package1" style does not work. Above codes tested on python
2.6.6, windows xp sp2. Thanks for explanations :)
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Re: [Tutor] How to use a module when only import package

[leechau]

Steven wrote:

leechau wrote:

I wrote module1 in package1, and want to use a method named 'method1' in
module1, the caller(test.py) is like this:

import package1
package1.module1.method1()

[...]

When i run test.py, the output is:
AttributeError: 'module' object has no attribute 'module1'
File "e:\MyDoc\GODU_BVT\test.py", line 2, in 
  package1.module1.method1()

If test.py is modified to:
import package1.module1
...
then everything goes well.


Yes, that is correct, and that is a deliberate design.

What if your package had a 1000 sub-modules, each of which were big? You
wouldn't want loading the main package to automatically load all 1000
sub-modules, if you only needed 1.

You either import the sub-module by hand:

import package1.module1

and now you can use package1.module1.method1 (not really a method,
actually a function). If you want module1 to automatically be available
after importing the package, include one of these in the package1
__init__.py file:

import module1  # should work in Python 2


and now package1 will include the module1 in its namespace.


--
Steven


Thanks for Steven's exellent and patient explanations. How should I do 
if automatically import a module in Python 3? Thanks again.


--
leechau
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[Tutor] How to design the structure of multi-steps(and substeps) scripts

[leechau]

Hi everybody. I wrote a script to run BVT and it's code structure like this:

def step1:
local_var1 = ...
# some other variable definitions for step1
def substep11:
pass
def substep12:
pass
# more substeps

def step2:
local_var1 = ...
# some other variable definitions for step2
def substep21:
pass
def substep22:
pass
# more substeps

# more steps ...

def stepN:
#vars and substeps...

global_var1 = ...
# more global var definitions...
if step1.return_success:
step2
step3
...
stepN

As you see, this script consists of serveral steps(a list of commands),
and a step often consists of several substeps. I used to put all the
steps in one module, where one step corresponding to one funciton and
one substep corresponding to one nested function. It's now a headache to
maintain this script because of totally 1000+ lines of code. Meanwhile
when I manipulate different projects with this script I need to modify
the value of some variables and detailed task logic. Obviously it's a
dirty work to modify the source code directly for different projects. So
I wonder if I should put different steps in different modules to shorten
the length of each module? If I should put the default value of a
variable and high level task logic in a abstract class, and define
specific value and detailed task logic in concrete subclass? Is there
any design patterns available for this kind of multi-steps scripts?

Thanks!
-- 
leechau
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