programmnig advise needed

[mitsura at skynet.be]

Thanks for the feedback! It is a very good idea to use dictionaries. I
will try to implemented it this way.

Thanks,

Kris


Andrea Griffini schreef:
> On 7 Jun 2005 12:14:45 -0700, mitsura at skynet.be wrote:
>
> >I am writing a Python program that needs to read XML files and contruct
> >a tree object from the XML file (using wxTree).
>
> Supposing your XML file has a single top level node (so that it's a
> legal XML file) then the following code should be able to read it...
>
> #########
> from elementtree import ElementTree as ET
>
> class Node:
>     def __init__(self, xmlnode):
>         self.xmlnode = xmlnode
>         self.children = []
>
> def loadtree(f):
>     root = ET.parse(f).getroot()
>     nodes = {}
>     for x in root:
>         if x.tag.startswith("element"):
>             nodes[x.tag] = Node(x)
>     for x in root.findall("association"):
>         name = x.find("Name").text
>         parent = x.find("Parent").text
>         nodes[parent].children.append(nodes.pop(name))
>     assert len(nodes) == 1
>     return nodes.popitem()[1]
> ##########
>
> The idea is to create a node with an empty list of
> logical children and then for every association
> removing the child node from the global pool (a dict
> indexed by node name) to place it in its parent.
> I assumed that the nodes are in random order, but
> that the associations are sorted bottom-up in
> the tree. If this is not the case then you should
> keep TWO dicts, removing from only one of them
> the children when you process an association,
> and looking up the parent in the *other* dict that
> is not changed during processing of associations.
> The dict from who you are removing the children
> will allow you to detect logical errors in the file
> (i.e. a node having two parents - you won't find
> that node in the dict the second time - and absence
> of a single root - you won't end up with a single
> element in the dict after processing all
> associations -).
> 
> HTH
> Andrea