tree data structure

[Tom Good]

Padraig Brady <Padraig at Linux.ie> wrote in message news:<Ti1e9.2864$cP3.6124 at news.iol.ie>...

> > {'S2': ['S0', 'S1', 'S3'], 'S1': ['Q2'], 'S0': ['Q1'], 'L0': ['S2']}
> 
> Interesting I didn't know about setdefault.
> However how would you iterate over the above?

from __future__ import generators

def treeIterator(tree):
    for key in tree.keys():
        yield key
        for val in tree[key]:
            if not tree.has_key(val):
                yield val


if __name__ == '__main__':
    tree = {'S2': ['S0', 'S1', 'S3'], 'S1': ['Q2'], 'S0': ['Q1'], 'L0': ['S2']}
    for node in treeIterator(tree):
        print node