Question about extending tuple

[Georg Brandl]

abcd schrieb:
> I wanted to extend tuple but ran into a problem.  Here is what I
> thought would work
> 
> class MyTuple(tuple):
>     def __init__(self, *args):
>         tuple.__init__(self, args)
> 
> x = MyTuple(1,2,3,4)
> 
> That gives me...
> 
> TypeError: tuple() takes at most 1 argument (4 given).
> 
> However, this call works:
> 
> x = MyTuple((1,2,3,4))
> 
> I am perplexed only because "args" is a tuple by the definition of
> *args.  Anyone?

As an immutable type, tuple makes use of __new__.

class MyTuple(tuple):
     def __new__(cls, *args):
         return tuple.__new__(cls, args)

should work.

Georg