One thing about classes that really tripped me up when I first started using
classes was 'self' before the variable. When you have ' self.variable '
that is a variable that can be referenced by the parent. If there's no
'self' before the variable, you can not.
For instance, if you have a routine:
class Dog:
def __init__(self, color):
self.color = color
age = 16
buster = Dog('black')
buddy = Dog('tan')
roofus = Dog('gray')
print buster.color
print buddy.color
print roofus.color
will yield the text as answers: black, tan, gray
print buster.age
print buddy.age
print roofus.age
will -*NOT*- yield 16, 16, 16. It will error out, because you can not
reference age without pre-pending a 'self.'
-Dave
"John Fouhy" <[EMAIL PROTECTED]> wrote in message
news:[EMAIL PROTECTED]
> On 13/01/06, Christopher Spears <[EMAIL PROTECTED]> wrote:
> > I just read about __init__ in the chapter on operator
> > overloading in Learning Python. What is __init__
> > exactly? Is it a special function that you can use to
> > initialize attributes in an object upon creation?
>
> Pretty much ... Have you read about defining your own classes yet? [I
> don't have Learning Python]
>
> If you haven't, then don't worry about it --- the book will surely
> cover __init__ when you get to defining classes.
>
> But, either way, here is a short example:
>
> >>> class MyClass(object):
> ... def __init__(self):
> ... print 'Initialising MyClass instance now...'
> ... self.x = 3
> ...
> >>> m = MyClass()
> Initialising MyClass instance now...
> >>> m.x
> 3
>
> --
> John.
> _______________________________________________
> Tutor maillist - Tutor@python.org
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>
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