xml.dom.minidom for Parsing XML Document

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∟xml.dom.minidom for Parsing XML Document

This section provides a tutorial example on how to parse an existing XML document into DOM object tree with Python xml.dom.minidom package.

xml.dom.minidom sub-package offers the following functionalities to parse an existing XML document into a DOM object tree and access its elements/attributes.

doc = xml.dom.minidom.parse(file) - Parses an XML document in a file into a DOM document.
doc = xml.dom.minidom.parseString(xml_string) - Parses an XML string into a DOM document.
root = doc.documentElement - Document property represents the root element.
list = doc.getElementsByTagName("tag_name") - Returns a list of elements that matches the tag name.
ele.getAttribute(name) - Returns the value an attribute from the element.
ele.tagName - Property represents the tag name of the element.
map = ele.Attributes - A NameNodeMap object representing all attributes of the element. It supports map.item(i) and map.length in the API for you to loop through each attribute.
map.length - Property represents the number of items in the map.
map.item(i) - Returns the item of a given index in the map.
list = ele.childNodes - A NodeList object representing the list of all child nodes including sub-elements and text nodes. It supports map.item(i) and map.length in the API for you to loop through each child node. It also supports Python sequence API to be used in "for n in list" statements.
attr.name - Property represents the name of the attribute
attr.value - Property represents the value of the attribute
node.nodeName - Property represents the name of the node, which could a document, an element or a text node.
node.nodeType - Property represents the type of the node.
xml.dom.minidom.Element.TEXT_NODE | ELEMENT_NODE | DOCUMENT_NODE | ATTRIBUTE_NODE - Enumerate value for different types of node.
text.data - Property represents the text of the text node.

Here is an example Python script that parses and browses an XML document using the xml.dom.minidom sub-package:

#- minidom_Parse_XML.py
#- Copyright (c) 2018 HerongYang.com. All Rights Reserved.
#
import xml.dom.minidom

#- Browse a node recursively 
def browseNode(node, pad):
  print(pad+node.nodeName)

  map = node.attributes
  for i in range(map.length):
    print(pad+" |@"+map.item(i).name+": "+map.item(i).value)

  list = node.childNodes
  for child in list:
    if child.nodeType == xml.dom.minidom.Element.ELEMENT_NODE:
      browseNode(child, pad+" ")
    elif child.nodeType == xml.dom.minidom.Element.TEXT_NODE:
      text = child.nodeValue.strip()
      if len(text)>0:
        print(pad+" |"+child.nodeName+": "+text)
    else:
      print("Something went wrong!")

#- Parse an existing XML file into a DOM document
doc = xml.dom.minidom.parse("dictionary.xml")
root = doc.documentElement

browseNode(root, "")

Use the program from the last tutorial minidom_Build_XML.py to create an XML file. Then parse it with minidom_Parse_XML.py:

herong> python minidom_Build_XML.py > dictionary.xml 

herong> python minidom_Parse_XML.py

dictionary
 word
  update
   |@date: 2100-01-01
  name
   |@is_acronym: true
   |#text: DTD
  definition
   |#text: Document Type Definition

Notes on the Python script and output:

"text = child.nodeValue.strip()" is used to strip white spaces padded in the XML document for the pretty format.
The "@" sign is used to differentiate attributes from child text nodes.