unbalanced tree iteration issue

[Alex Boyko]

Dear All!

I have deal with large unbalanced trees and I have to implement post-order
tree traversal. My first attempt is shown below ("Node" and "Tree" classes)
and based on recursive generators approach.

class Node():
    def __init__(self,value):
        self.childs = []
        self.value = value

class Tree():

    def __init__(self, root):
        self.root = root
        self.numberCells = 1

    def add(self, node, child):
        node.childs.append(child)
        self.numberCells+=1

    def __iter__(self):
        return self.postorder(self.root)

    def postorder(self, node):
        if node:
            for child in node.childs:
                for n in self.postorder(child):
                    yield n
            yield node


It works fine for small test trees. But, my tree has approximately 300000
nodes, and shown post order traversal with generators takes 80 sec against 1
sec with simple recursive routine:


def recursiveFromTop(node):
    for child in node.childs:
        recursiveFromTop(child)
        ## here I can do some computations with current node's data


So, I'd like to know how should I implement (if it's possible of course)
__iter__ for my tree class based on recursion without generators? Please,
can You show me the ways?
because I'm very passionate in idea iterate through my tree with simple:

for node in tree:
   do something with node


Thanks in Advance!
Best Regards!
Alex
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