[Tutor] Inheritance

[Alan Gauld]

> One question is if class A inherits from class B and C. And
then B inherits
> from M and N. And C inherits from F and G, while F and N
inherit from class
> z which inherits from object, what is the name resolution.
>
>
>
>                        Z
>                  M  N    F  G
>                   B       C
>                       A
>

A,B,M,N,Z,C,F,Z,G

I think.

Python works left to right in declaration order. And it stops
with the first successful find.

> Also can someone explain to me what super() does,

Sorry, its a new feature and I've not got round to using it
yet. I just tried a wee experiment and it didn't work how
I expected so I need to go rad the docs I think! :-)

> Next using the same classes as above, if z.__init__: connects
to a database,
> how can I make sure that it is only called once,

You could test for the existence of the connection in the
init()... But it looks a bit grubby, thee might be a better
way someone else can think of...

class Z:
   def __init__(self,Database):
      try:
          if self.db: pass
      except AttributeError:
          self.db = connect(Database)



> class test:
>   def __init__():
>       self.x = 'hello'
>   print self.x
>
>
> Tha above code raises an error. What can I do to make it work??

Add a self parameter to the init method

    def __init__(self):


HTH,

Alan G.