Re: [Tutor] elementtree, lists, and dictionaries

[Kent Johnson]

If you iterate over the author nodes you can check the user name and password 
of each in turn.
Not tested code!
def authenticateAuthor(author, password):
    authorxml = 'author.xml'
    path = os.path.join(xml, authorxml)
    if not os.path.exists(path):
        return False, False
    else:
        tree = E.ElementTree(file=path)
        for authorNode in tree.getiterator('author'):
            user = authorNode.find('user').text
            pass = authorNode.find('password').text
            if author == user:
                if password == pass:
                    return True, True
                else:
                    return False, True
        return False, True
Luis N wrote:
Hi,
This code works, but I don't like it much:
def authenticateAuthor(author, password):
    authorxml = 'author.xml'
    path = os.path.join(xml, authorxml)
    try: if not os.path.exists(path):
        authorfile = False
    else:
        authorfile = True
        tree = E.ElementTree(file=path)
        u = tree.getiterator('user')
        p = tree.getiterator('password')
Here you could say
  d = dict( (unode.text, pnode.text) for unode, pnode in zip(u, p))
        ul = []
        pl = []
        for unode in u:
            ul.append(unode.text)
        for pnode in p:
            pl.append(pnode.text)
        d = {}
        for i in range(len(ul)):
            d[ul[i]] = pl[i]

        if d.has_key(author):
            if d.get(author) == password:
                auth = True
            else:
                auth = False
or
  try:
    if d[author] == password:
      auth = True
  except KeyError:
    auth = False
or, if you are sure password will not be None, just skip the has_key():
  if d.get(author) == password:
    ...
(I hate using has_key() followed by a get()...
            return auth, authorfile
It assumes a great deal, such as that there is no chance that there
will be more users then there are passwords, etc. given an xml
document format such as:
<root>
    <author>
        <user>authorname</user>
        <password>authorpassword</password>
    </author>
</root>
I don't like how I'm making two lists and then turning them into a
dictionary. It seems unpythonic.
Suggestions are appreciated.
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_______________________________________________
Tutor maillist  -  Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor