[Tutor] Instance into another instance

[Gregor Lingl]

Ismael Garrido schrieb:
> Hello.
> 
> This is my code:
> class Node:
>    def __init__(self, tag, value=None, **kwargs):
>        self.tag = tag
>        self.value = value
>        self.kwargs = kwargs
>        self.childs = []
> 
>    def addChild(self, tag, value=None, **kwargs):
>        node = Node(tag, value, kwargs)
>        self.childs.append(node)
> 
>    def __repr__(self):
>        return "Tag %s ; value %s ; kwargs %s ; childs %s" % (self.tag, 
> self.value, self.kwargs, self.childs)
>        And this is what I do to test it:
>  >>> ppal = Node("Test", value="Test")
>  >>> ppal.addChild("test", value=2)
> 
> Traceback (most recent call last):
>  File "<pyshell#75>", line 1, in -toplevel-
>    ppal.addChild("test", value=2)
>  File "...node.py", line 10, in addChild
>    node = Node(tag, value, kwargs)
> TypeError: __init__() takes at most 3 arguments (4 given)

This means, afaik, __init__() takes at most 3 non-keyword arguments
(plus an arbitrary number of keyword-arguments).

You passed 4 non-keyword - arguments, the first beeing (implicitely)
self (i. e. node), and then three more: tag, value, kwargs.
(In your case kwargs is the empty dictionary.)

I suppose you wanted to pass addChild's **kwargs
to Node's **kwargs, which goes like this:

    def addChild(self, tag, value=None, **kwargs):
        node = Node(tag, value, **kwargs)
        self.childs.append(node)

HTH,
Gregor

> 
> I don't understand. Why 4 arguments are given? What can I do to solve that?
> 
> The idea of the class is to be able to create a "tree". Where each node 
> can have subnodes, which in turn can have their subnodes...
> 
> Thanks
> Ismael
> 
> _______________________________________________
> Tutor maillist  -  Tutor at python.org
> http://mail.python.org/mailman/listinfo/tutor
> 
> 

-- 
Gregor Lingl
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