Search and remove element with elementTree in Python

Question

I have an XML document in which I want to search for some elements and if they match some criteria I would like to delete them

However, I cannot seem to be able to access the parent of the element so that I can delete it

file = open('test.xml', "r") elem = ElementTree.parse(file)  namespace = "{http://somens}"  props = elem.findall('.//{0}prop'.format(namespace)) for prop in props:     type = prop.attrib.get('type', None)     if type == 'json':         value = json.loads(prop.attrib['value'])         if value['name'] == 'Page1.Button1':             #here I need to access the parent of prop             # in order to delete the prop 

Is there a way I can do this?

Thanks

Answer 1

You can remove child elements with the according remove method. To remove an element you have to call its parents remove method. Unfortunately Element does not provide a reference to its parents, so it is up to you to keep track of parent/child relations (which speaks against your use of elem.findall())

A proposed solution could look like this:

root = elem.getroot() for child in root:     if child.name != "prop":         continue     if True:# TODO: do your check here!         root.remove(child) 

PS: don't use prop.attrib.get(), use prop.get(), as explained here.

Answer 2

You could use xpath to select an Element's parent.

file = open('test.xml', "r") elem = ElementTree.parse(file)  namespace = "{http://somens}"  props = elem.findall('.//{0}prop'.format(namespace)) for prop in props:     type = prop.get('type', None)     if type == 'json':         value = json.loads(prop.attrib['value'])         if value['name'] == 'Page1.Button1':             # Get parent and remove this prop             parent = prop.find("..")             parent.remove(prop) 

http://docs.python.org/2/library/xml.etree.elementtree.html#supported-xpath-syntax

Except if you try that it doesn't work: http://elmpowered.skawaii.net/?p=74

So instead you have to:

file = open('test.xml', "r") elem = ElementTree.parse(file)  namespace = "{http://somens}" search = './/{0}prop'.format(namespace)  # Use xpath to get all parents of props     prop_parents = elem.findall(search + '/..') for parent in prop_parents:     # Still have to find and iterate through child props     for prop in parent.findall(search):         type = prop.get('type', None)         if type == 'json':             value = json.loads(prop.attrib['value'])             if value['name'] == 'Page1.Button1':                 parent.remove(prop) 

It is two searches and a nested loop. The inner search is only on Elements known to contain props as first children, but that may not mean much depending on your schema.