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Modifying element in xml using python

can anyone please explain how to modify xml element in python using elementtree.
I want to keep the rego AD-4214 and change make 'Tata' into 'Nissan' and model 'Sumo' into 'Skyline'.

If rewriting the entire file is acceptable1, the easiest way would be to turn the xml file into a dictionary (see for example here: How to convert an XML string to a dictionary?), do your modifications on that dictionary, and convert this dict back to xml (like for example here: https://pypi.org/project/dicttoxml/)
1 Consider lost formatting: whitespace, number formats etc may not be preserved by this.

This should work:
import xml.etree.ElementTree as ET
tree = ET.parse('your_xml_source.xml')
root = tree.getroot()
root[1][1].text = "Nissan"
root[1][2].text = "Skyline"
getroot() gives you the root element (<motorvehicle>), [1] selects its second child, the <vehicle> with rego AD-4214. The secondary indexing, [1] and [2], gives you AD-4214's <make> and <model> respectively. Then using the text attribute, you can change their text content.

XML writing- new file

I am using Python to pick a specific set of values from my XML:
children = root[2].getchildren()
for child in children:
ET.dump(child)
Once I use this I get a print of exactly what I need from my XML. I can also change the root number to access different data. I want to export this value as a new separate xml, however when I use :
tree.write('new.xml')
It exports the entire XML, as before. It is not just the value I specified above, value I selected.

Python XML 'TypeError: must be xml.etree.ElementTree.Element, not str'

I currently am trying to build an XML file from a CSV file. Currently my code reads the CSV file to data and begins creating the XML from the data that is stored within the CSV.
CSV Example:
Element,XMLFile
SubElement,XMLName,XMLFile
SubElement,XMLDate,XMLName
SubElement,XMLInformation,XMLDate
SubElement,XMLTime,XMLName
Expected Output:
<XMLFile>
<XMLName>
<XMLDate>
<XMLInformation />
</XMLDate>
<XMLTime />
</XMLName>
</XMLFile>
Currently my code attempts to look at the CSV to see what the parent is for the new subelement:
# Defines main element
# xmlElement = xml.Element(XMLFile)
xmlElement = xml.Element(csvData[rowNumber][columnNumber])
# Should Define desired parent (FAIL) and SubElement name (PASS)
# xmlSubElement = xml.SubElement(XMLFile, XMLName)
xmlSubElement = xml.SubElement(csvData[rowNumber][columnNumber + 2], csvData[rowNumber][columnNumber + 1])
When the code attempts to use the CSV source string as the parent parameter, Python 3.5 generates the following error:
TypeError: must be xml.etree.ElementTree.Element, not str
Known cause of the error is that the parent paramenter is being returned as a string, when it is expected to be an Element or SubElement.
Is it possible to recall the stored value from the CSV and have it reference the Element or SubElement, instead of a string? The goal is to allow the code to read the CSV file and assign any SubElement to the parent listed in the CSV.

I cannot tell for sure, but it looks like you are doing:
ElementTree.SubElement(str, str)
when you should be doing:
ElementTree.SubElement(Element, str)
It also seems like you already know this. The real question, then, is how are you going to reference the parent object when you only know its tag string? You could search for Elements in the ElementTree with that particular tag string, but this is generally not a good idea as XML allows multiple instances of similar elements.
I would suggest you either:
Find a strategy to store references to parent elements
See if there is a way to uniquely identify the parent element using XPath

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

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

XML to store system paths in Python with lxml

I'm using an xml file to store configurations for a software.
One of theese configurations would be a system path like
> set_value = "c:\\test\\3 tests\\test"
i can store it by using:
> setting = etree.SubElement(settings,
> "setting", name=tmp_set_name, type =
> set_type , value= set_value)
If I use
doc.write(output_file, method='xml',encoding = 'utf-8', compression=0)
the file would be:
< setting type="str" name="MyPath" value="c:\test\3 tests\test"/>
Now I read it again with the etree.parse method
I obtain an etree child object with a string value, but the string
contains the
\3
character and if i try to use it to write again to xml it will be interpreted !!!!! So i cannot use it anymore as a path
Maybe i'm only missing a simple string operation, but I cannot see it =)
How would you solve it in a smart way ?
This is an example, but what is the best way, you think to store paths in xml and parse them with lxml ?
Thank you !!

Now I read it again with the
etree.parse method
I obtain an etree child object with a
string value, but the string contains
the
\3
character and if i try to use it to
write again to xml it will be
interpreted !!!!!
I just tried that, and it doesn't get "interpreted". The elements attributes as returned after parsed is:
{'type': 'str', 'name': 'yowza!', 'value': 'c:\\test\\3 tests\\test'}
So as you see this works just as you expected it to work. If you really have this problem, you are doing something else than what you are saying. Show us the real code, or make a small example code where you demonstrate the problem and use that.