gistfile1.py

# -*- coding: utf-8 -*-
"""
>>> root = etree.Element('foo')
>>> el = get_path('bar/baz', root).text = 'foobaz'
>>> etree.tostring(root)
'<foo><bar><baz>foobaz</baz></bar></foo>'
>>> get_path('bar/gaz', root).text = 'foogaz'
>>> etree.tostring(root)
'<foo><bar><baz>foobaz</baz><gaz>foogaz</gaz></bar></foo>'
"""
from functools import reduce

from lxml import etree


def get_path(path, root):
    return reduce(get_or_set, path.split('/'), root)


def get_or_set(root, child):
    el = root.find(child)
    if el is None:
        el = etree.SubElement(root, child)
    return el


if __name__ == '__main__':
    import doctest
    doctest.testmod()