xml_references.py

#!/usr/bin/env python
# coding: utf-8

import xml.etree.ElementTree as etree
from pprint import pprint

data = """
<data>
    <parts>
        <part name="komplexes Teil">
            <elem keyref="a"/>
            <elem keyref="b"/>
            <elem keyref="c"/>
        </part>
        <part name="simples Teil">
            <elem keyref="b"/>
            <elem keyref="c"/>
        </part>
    </parts>
    <elements>
        <elem key="a" name="abc"/>
        <elem key="b" name="def"/>
        <elem key="c" name="ghi"/>
    </elements>
</data>
"""

class Element:

    def __init__(self, key, name):
        self.key = key
        self.name = name
        
    def __str__(self):
        return "Element {}: {}".format(self.key, self.name)


def get_parts(root, elements):
    parts = {}
    for node in root.findall(".//parts/part"):
        # Hier benutzen wir das Mapping key -> Element-Objekt, um die
        # Teilemengen aus Element-Objekten aufzubauen
        part = [elements[part_node.attrib["keyref"]] for part_node in node]
        parts[node.attrib["name"]] = part
    return parts
 
    
def get_elements(root):
    elements = {}
    for node in root.findall(".//elements/elem"):
        element = Element(node.attrib["key"], node.attrib["name"])
        elements[element.key] = element
    return elements


def parse_from_xml(data):
    root = etree.fromstring(data)
    elements = get_elements(root)
    return get_parts(root, elements)
    
        
def main():
    parts = parse_from_xml(data)
    print("Habe {} Parts gefunden".format(len(parts)))
    for key, part in parts.items():
        print("Part '{}':".format(key))
        for element in part:
            print("  - {}".format(element))


if __name__ == "__main__":
    main()