That's awsome, but it does not explain getitem. Maybe it should be:
class MyList(object):
def __init__(self, *a): self.a = list(a)
def __len__(self): return len(self.a)
def __getitem__(self, i): return self.a[i]
def __setitem__(self, i, j): self.a[i] = j
b=MyList(3,4,5)
print b[1]
b[1]=7
print b[0]
On Sep 13, 5:06 am, b vivek <[email protected]> wrote:
> Use this:-
>
> class MyList(object):
> def __init__(self, *a): self.a = list(a)#this has to be a list, was a
> tuple earlier
> def __len__(self): return len(self.a)
> def __getitem__(self, i): return self.a[i]
> def __setitem__(self, i, j): self.a[i] = j
> b=MyList(3,4,5)
> print b[1]
> b[1]=7#self-explanatory
> print b.a
>
> On Mon, Sep 13, 2010 at 8:10 AM, guruyaya <[email protected]> wrote:
> > In chapter 2, on the code example of "Special Attributes, Methods and
> > Operators", we have
>
> > class MyList(object)
> > def __init__(self, *a): self.a = a
> > def __len__(self): return len(self.a)
> > def __getitem__(self, i): return self.a[i]
> > def __setitem__(self, i, j): self.a[i] = j
> > b = MyList(3, 4, 5)
> > print b[1]
> > a[1] = 7
> > print b.a
>
> > 1. The first line should be
> > class MyList(object):
>
> > 2. Running line 9 of the code produces this exception:
> > >>> a[1] = 7
> > Traceback (most recent call last):
> > File "<stdin>", line 1, in <module>
> > NameError: name 'a' is not defined
>
> > I'm not sure what was intended to be demonstrated there, as even b[1]
> > = 7 produces an excption, but it's not working.
>
>
