Search and remove element with elementTree in Python

user_272877 0
Viewed 68182

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

elementtree python
8 Answers

I like to use an XPath expression for this kind of filtering. Unless I know otherwise, such an expression must be applied at the root level, which means I can't just get a parent and apply the same expression on that parent. However, it seems to me that there is a nice and flexible solution that should work with any supported XPath, as long as none of the sought nodes is the root. It goes something like this:

root = elem.getroot()
# Find all nodes matching the filter string (flt)
nodes = root.findall(flt)
while len(nodes):
    # As long as there are nodes, there should be parents
    # Get the first of all parents to the found nodes
    parent = root.findall(flt+'/..')[0]
    # Use this parent to remove the first node
    parent.remove(nodes[0])
    # Find all remaining nodes
    nodes = root.findall(flt)
user_39588430

I also used XPath for this issue, but in a different way:

root = elem.getroot()    
elementName = "YourElement"
#this will find all the parents of the elements with elementName
for elementParent in root.findall(".//{}/..".format(elementName)):
   #this will find all the elements under the parent, and remove them
   for element in elementParent.findall("{}".format(elementName)):
      elementParent.remove(element)
user_34525590

I would like only to add a comment on the accepted answer, but my lack of reputation doesn't allow me to. I wanted to add that it is important to add .findall("*")to the iterator to avoid issues, as stated in the documentation:

Note that concurrent modification while iterating can lead to problems, just like when iterating and modifying Python lists or dicts. Therefore, the example first collects all matching elements with root.findall(), and only then iterates over the list of matches.

Therefore, in the accepted answer the iteration should be for child in root.findal("*"):instead of for child in root:. Not doing so made my code skip some elements from the list.

user_107748890
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