Making a tree out of a 2 column list

[Peter Otten]

Sebastian Bassi wrote:

> On 14 Apr 2007 09:32:07 -0700, mensanator at aol.com <mensanator at aol.com>
wrote:
> 
> > def tree_path(key,tree,indent):
> >     print '\t'*indent,key
> >     if tree.has_key(key):
> >         for m in tree[key]:
> >             tree_path(m,tree,indent+1)
> >     return
> 
> Thank you. It worked!.
> I changed it a bit to return a list with the results:
> 
> def tree_path(key,tree,hijos):
>         hijos.append(key)
>         if tree.has_key(key):
>                 for m in tree[key]:
>                         tree_path(m,tree,hijos)
>         return hijos
> 
> Then I call it like this:
> 
> MyList=tree_path(9608,tree,[])

Depending on your input data you may need to add some cycle detection. 
For example, try it with

tree_path(1, {1:[2], 2:[1]}, [])

Peter