XML ElementTree with pretty print

Question

1.) if you look at the following tags and the spaces of my xml-output you will notice that the spaces are not that correct, cause of the code in 2.)

• <SD-ID-Gesamt> & </SD-ID-Gesamt>
• <Lage> & </Lage>
• <Parameter> & </Parameter>

Current output:

<SD-ID-Gesart>
    <SD-ID-Code>
        <SD-ID>DD-RE-1.0G-10</SD-ID>
        <Lage>
            <XP>14.84</XP>
            <YP>73.19</YP>
            <ZP>7.92</ZP>
            <WKS>95.32</WKS>
            </Lage>
        <Parameter>
            <Form>Rectangle</Form>
            <Art>Deckendurchbruch/Art>
            <Gewerk>-HT-SAN-DURCHBRUCH</Gewerk>
            <Ebene>1.OG OKFF +4,50 m</Ebene>
            <Breite>1,800000</Breite>
            <Höhe>0,500000</Höhe>
            <Tiefe>0,450000</Tiefe>
            <Status_Neu>0</Status_Neu>
            <Status_Geändert>1</Status_Geändert>
            </Parameter>
    <SD-ID-Code>

---

2.) I am calling indent() to pretty print my xml-files. It is working almost as wished, except from one little mistake in the code you see below. The mistake you can see in the xml-output in the picture above.

def indent(elem, level=0):
i = "\n" + level*"  "
if len(elem):
    if not elem.text or not elem.text.strip():
        elem.text = i + ""
    if not elem.tail or not elem.tail.strip():
        elem.tail = i
for elem in elem:
    indent(elem, level+1)
    if not elem.tail or not elem.tail.strip():
        elem.tail = i
    else:
        if level and (not elem.tail or not elem.tail.strip()):
            elem.tail = i

---

3.) with the code you see next i create the ElementTree, when it went through indent().

indent(sd)
tree = ET.ElementTree(sd)
tree.write(open(pfad + '\\'+ datei_name + '.xml', "w"), encoding='utf-8', 
xml_declaration=True, method='xml')

---

I need to edit the definition of the indent() indent function to get the spaces correct. In that case I really have no idea how to put back the spaces when the tag is equal. I would be very very happy if you could help me getting that fixed.

Answer 1

Update: See xml.etree.ElementTree.indent as of Python 3.9.

I couldn't reproduce the bad indentation from your example, but according to http://effbot.org/zone/element-lib.htm#prettyprint, your function is mis-copied. For these lines:

if not elem.text or not elem.text.strip():
    elem.text = i + ""

There should be two space between the quotes:

if not elem.text or not elem.text.strip():
  elem.text = i + "  "

I ran this code and it displays properly.

from xml.etree import ElementTree as et

def indent(elem, level=0):
  i = "\n" + level*"  "
  if len(elem):
    if not elem.text or not elem.text.strip():
      elem.text = i + "  "
    if not elem.tail or not elem.tail.strip():
      elem.tail = i
    for e in elem:
      indent(e, level+1)
    if not e.tail or not e.tail.strip():
      e.tail = i
  else:
    if level and (not elem.tail or not elem.tail.strip()):
      elem.tail = i

data = '''<one><two><three>3</three><four>4</four></two></one>'''
tree = et.fromstring(data)
indent(tree)
et.dump(tree)

Output:

<one>
  <two>
    <three>3</three>
    <four>4</four>
  </two>
</one>

Notes for future:

• Images of text can't be copied so I leave it as an exercise for you to test on your own XML.
• Cut-n-paste exact code and input data as text to reproduce the issue to make it easy for answers to reproduce the issue.