Convert a dot notation string to object to access lxml objects python

Question

I am trying to update the xml using object notation using lxml objectify.

<xml>
  <fruit>
    <citrus>
        <lemon />
    </citrus>
  </fruit>  
</xml>

I am trying to add another fruit called mango using lxml objectify like

root = lxml.objectify.fromstring(xml_string)
root.fruit.citrus = 'orange'

def update(path, value):
    // code

update('fruit.citrus', 'orange')

I would like to pass a string like 'fruit.citrus' because I cannot pass an object fruit.citrus.

How do I achieve this in Python ie how do I execute the code 'root.fruit.citrus = 'orange' inside the update function. How to convert string to object?

Answer 1

Try Below solution:

import lxml.objectify, lxml.etree

xml = '<xml>  <fruit>    <citrus>        <lemon />    </citrus>  </fruit> </xml>'

root = lxml.objectify.fromstring(xml)

print("Before:")
print(lxml.etree.tostring(root))


def update(path, value):
    parent = None
    lst = path.split('.')
    while lst:
        ele = lst.pop(0)
        parent = getattr(root, ele) if parent is None else getattr(parent, ele)
    lxml.etree.SubElement(parent, value)


update('fruit.citrus', 'orange')

print("After:")
print(lxml.etree.tostring(root))

Output:

Before:
b'<xml><fruit><citrus><lemon/></citrus></fruit></xml>'
After:
b'<xml><fruit><citrus><lemon/><orange/></citrus></fruit></xml>'