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New in version 2.0.
xml.dom.minidom is a light-weight implementation of the
Document Object Model interface. It is intended to be
simpler than the full DOM and also significantly smaller.
DOM applications typically start by parsing some XML into a DOM. With
xml.dom.minidom, this is done through the parse functions:
from xml.dom.minidom import parse, parseString
dom1 = parse('c:\\temp\\mydata.xml') # parse an XML file by name
datasource = open('c:\\temp\\mydata.xml')
dom2 = parse(datasource) # parse an open file
dom3 = parseString('<myxml>Some data<empty/> some more data</myxml>')
The parse() function can take either a filename or an open
file object.
| parse( |
filename_or_file, parser) |
-
Return a Document from the given input. filename_or_file
may be either a file name, or a file-like object. parser, if
given, must be a SAX2 parser object. This function will change the
document handler of the parser and activate namespace support; other
parser configuration (like setting an entity resolver) must have been
done in advance.
If you have XML in a string, you can use the
parseString() function instead:
| parseString( |
string[, parser]) |
-
Return a Document that represents the string. This
method creates a StringIO object for the string and passes
that on to parse.
Both functions return a Document object representing the
content of the document.
What the parse() and parseString() functions do
is connect an XML parser with a ``DOM builder'' that can accept parse
events from any SAX parser and convert them into a DOM tree. The name
of the functions are perhaps misleading, but are easy to grasp when
learning the interfaces. The parsing of the document will be
completed before these functions return; it's simply that these
functions do not provide a parser implementation themselves.
You can also create a Document by calling a method on a ``DOM
Implementation'' object. You can get this object either by calling
the getDOMImplementation() function in the
xml.dom package or the xml.dom.minidom module.
Using the implementation from the xml.dom.minidom module will
always return a Document instance from the minidom
implementation, while the version from xml.dom may provide
an alternate implementation (this is likely if you have the
PyXML package installed). Once
you have a Document, you can add child nodes to it to populate
the DOM:
from xml.dom.minidom import getDOMImplementation
impl = getDOMImplementation()
newdoc = impl.createDocument(None, "some_tag", None)
top_element = newdoc.documentElement
text = newdoc.createTextNode('Some textual content.')
top_element.appendChild(text)
Once you have a DOM document object, you can access the parts of your
XML document through its properties and methods. These properties are
defined in the DOM specification. The main property of the document
object is the documentElement property. It gives you the
main element in the XML document: the one that holds all others. Here
is an example program:
dom3 = parseString("<myxml>Some data</myxml>")
assert dom3.documentElement.tagName == "myxml"
When you are finished with a DOM, you should clean it up. This is
necessary because some versions of Python do not support garbage
collection of objects that refer to each other in a cycle. Until this
restriction is removed from all versions of Python, it is safest to
write your code as if cycles would not be cleaned up.
The way to clean up a DOM is to call its unlink() method:
dom1.unlink()
dom2.unlink()
dom3.unlink()
unlink() is a xml.dom.minidom-specific extension to
the DOM API. After calling unlink() on a node, the node and
its descendants are essentially useless.
Release 2.4.5, documentation updated on 18 October 2006.
See About this document... for information on suggesting changes.
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