python - how to write empty tree node as empty string to xml file

Question

I want to remove elements of a certain tag value and then write out the .xml file WITHOUT any tags for those deleted elements; is my only option to create a new tre

Answer 1

import lxml.etree as et

xml  = et.parse("test.xml")

for node in xml.xpath("//neighbor"):
    node.getparent().remove(node)


xml.write("out.xml",encoding="utf-8",xml_declaration=True)

Using elementTree, we need to find the parents of the neighbor nodes then find the neighbor nodes inside that parent and remove them:

from xml.etree import ElementTree as et

xml  = et.parse("test.xml")


for parent in xml.getroot().findall(".//neighbor/.."):
      for child in parent.findall("./neighbor"):
          parent.remove(child)


xml.write("out.xml",encoding="utf-8",xml_declaration=True)

Both will give you:

    
        1
        2008
        141100
        
    
        4
        2011
        59900
        
    
        68
        2011
        13600
        

Using your attribute logic and modifying the xml a bit like below:

x = """

    
        1
        2008
        141100
        
        
    
    
        4
        2011
        59900
           
        
    
    
        68
        2011
        13600
        
        
    
"""

Using lxml:

import lxml.etree as et

xml = et.fromstring(x)

for node in xml.xpath("//neighbor[not(@make) and not(@job) and not(@make)]"):
    node.getparent().remove(node)
print(et.tostring(xml))

Would give you:

 
    
        1
        2008
        141100
        
    
        4
        2011
        59900
        
        
    
        68
        2011
        13600
        
        

The same logic in ElementTree:

from xml.etree import ElementTree as et

xml = et.parse("test.xml").getroot()

atts = {"build", "job", "make"}

for parent in xml.findall(".//neighbor/.."):
    for child in parent.findall(".//neighbor")[:]:
        if not atts.issubset(child.attrib):
            parent.remove(child)

If you are using iter:

from xml.etree import ElementTree as et

xml = et.parse("test.xml")

for parent in xml.getroot().iter("*"):
    parent[:] = (child for child in parent if child.tag != "neighbor")

You can see we get the exact same output:

In [30]: !cat /home/padraic/untitled6/test.xml


    #
      
        1
        
        2008
      
        141100
        
        
    
    
        4
        2011
        59900
        
    
    
        68
        2011
        13600
        
        
    

In [31]: paste
def test():
    import lxml.etree as et
    xml = et.parse("/home/padraic/untitled6/test.xml")
    for node in xml.xpath("//neighbor"):
        node.getparent().remove(node)
    a = et.tostring(xml)
    from xml.etree import ElementTree as et
    xml = et.parse("/home/padraic/untitled6/test.xml")
    for parent in xml.getroot().iter("*"):
        parent[:] = (child for child in parent if child.tag != "neighbor")
    b = et.tostring(xml.getroot())
    assert  a == b

## -- End pasted text --

In [32]: test()