How to write XML declaration using xml.etree.ElementTree

Question

I am generating an XML document in Python using an ElementTree, but the tostring function doesn\'t include an XML declaration when converting to plaintext.

Answer 1

Easy

Sample for both Python 2 and 3 (encoding parameter must be utf8):

import xml.etree.ElementTree as ElementTree

tree = ElementTree.ElementTree(ElementTree.fromstring('123'))
root = tree.getroot()
print(ElementTree.tostring(root, encoding='utf8', method='xml'))

From Python 3.8 there is xml_declaration parameter for that stuff:

New in version 3.8: The xml_declaration and default_namespace parameters.

xml.etree.ElementTree.tostring(element, encoding="us-ascii", method="xml", *, xml_declaration=None, default_namespace=None, short_empty_elements=True) Generates a string representation of an XML element, including all subelements. element is an Element instance. encoding 1 is the output encoding (default is US-ASCII). Use encoding="unicode" to generate a Unicode string (otherwise, a bytestring is generated). method is either "xml", "html" or "text" (default is "xml"). xml_declaration, default_namespace and short_empty_elements has the same meaning as in ElementTree.write(). Returns an (optionally) encoded string containing the XML data.

Sample for Python 3.8 and higher:

import xml.etree.ElementTree as ElementTree

tree = ElementTree.ElementTree(ElementTree.fromstring('123'))
root = tree.getroot()
print(ElementTree.tostring(root, encoding='unicode', method='xml', xml_declaration=True))