Re: Define Constants

[Steven Bethard]

codecraig wrote:
Hi,
  I have a question about how to define constants.
  My directory structure looks like...
C:\
    --> abc.py
    --> utils
        --> __init__.py
        --> CustomThing.py
  Ok, CustomThing looks like...
TOP = 0
LEFT = 1
class CustomThing:
    def __init__(self):
        self.foo = "foo"

  so, from abc.py I have
from utils.CustomThing import CustomThing
print CustomThing.TOP
but i get an error: AttributeError: class 'CustomThing' has no
attribute 'TOP'
How can I access those??
Note that TOP and LEFT are delcared in the *module* CustomThing, not the 
*class* CustomThing which is what you get if you do

    from utils.CustomThing import CustomThing # the *class*
You should probably write your code as something like:
    import utils.CustomThing
    print utils.CustomThing.TOP
and if you need to use the class, write:
    t = utils.CustomThing.CustomThing() # create a new CustomThing
Also, if you've just started this, it might be worth checking out 
PEP8[1] which suggests that modules "should have short, lowercase names, 
without underscores".  If you're stuck with such a long module name, you 
might try:

    import utils.CustomThing as thing
    print thing.TOP
    t = thing.CustomThing()
STeVe
[1]http://www.python.org/peps/pep-0008.html
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