Python XML parsing - equivalent of "grep -v" in bash

This is one of my first forays into Python. I'd normally stick with bash, however Minidom seems to perfectly suite my needs for XML parsing, so I'm giving it a shot.

First question which I can't seem to figure out is, what's the equivalent for 'grep -v' when parsing a file?

Each object I'm pulling begins with a specific tag. If, within said tag, I want to exclude a row of data based off of a certain string embedded within the tag, how do I accomplish this?

Pseudo code that I've got now (no exclusion):

mainTag = xml.getElementsByTagName("network_object")
name = network_object.getElementsByTagName("Name")[0].firstChild.data

I'd like to see the data output all "name" fields, with the exception of strings that contain "cluster". Since I'll be doing multiple searches on network_objects, I believe I need to do it at that level, but don't know how.

Etree is giving me a ton of problems, can you give me some logic to do this with minidom?

This obviously doesn't work:

name = network_object.getElementsByTagName("Name")[0].firstChild.data
if name is not 'cluster' in name
continue

Solution

First of all, step away from the minidom module. Minidom is great if you already know the DOM from other languages and really do not want to learn any other API. There are easier alternatives available, right there in the standard library. I'd use the ElementTree API instead.

You generally just loop over matches, and skip over the ones that you want to exclude as you do so:

from xml.etree import ElementTree

tree = ElementTree.parse(somefile)

for name in tree.findall('.//network_object//Name'):
    if name.text is not None and 'cluster' in name.text:
        continue  # skip this one