Wayne Sutton wrote:
> OK, I'm a newbie...
> I'm trying to learn Python & have had fun with it so far. But I'm having
> trouble following the many code examples with the object "self." Can
> someone explain this usage in plain english?
>
> Thanks,
> Wayne
I'll give it a try..
When you have a class definition:
class Person(object):
def set_name(self, name):
self.name = name
The method "set_name", has no idea what your class instance is going to
called at this point. But it will need to know when it's called. So
for now "self" is just a argument waiting to be assigned a reference
later just like any other function argument. You can actually call it
anything you want but "self" is sort of a tradition.
leader = Person()
This creates an instance of your class and stores a reference to it in
the name "leader". Now that that you have an instance with a name. You
can use your class method to do something.
leader.set_name("John")
When you call a method of an instance, Python translates it to...
leader.set_name(leader, "John")
So "self" in your method definition gets assigned a reference to
"leader". "self" can then be used to access the other values and
methods stored in your class instance. Or in this case store a value in
your class instance. Basically "self" becomes a reference to the class
instance it is in.
self.name = name
is the same as ...
leader.name = name
But we didn't know it was going to be called "leader" when we wrote the
class. So self is a convienent place holder.
I hope this helped.
Cheers,
Ron
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