If you're using xml.etree.ElementTree.parse to parse from a file, then you can use xml.etree.ElementTree.fromstring to get the root Element of the document. Often you don't actually need an ElementTree.

See xml.etree.ElementTree

How do I convert ElementTree.Element to a String?

For Python 3:

xml_str = ElementTree.tostring(xml, encoding='unicode')

For Python 2:

xml_str = ElementTree.tostring(xml, encoding='utf-8')

For compatibility with both Python 2 & 3:

xml_str = ElementTree.tostring(xml).decode()

Example usage

from xml.etree import ElementTree

xml = ElementTree.Element("Person", Name="John")
xml_str = ElementTree.tostring(xml).decode()
print(xml_str)

Output:

<Person Name="John" />

Explanation

Despite what the name implies, ElementTree.tostring() returns a bytestring by default in Python 2 & 3. This is an issue in Python 3, which uses Unicode for strings.

In Python 2 you could use the str type for both text and binary data. Unfortunately this confluence of two different concepts could lead to brittle code which sometimes worked for either kind of data, sometimes not. [...]

To make the distinction between text and binary data clearer and more pronounced, [Python 3] made text and binary data distinct types that cannot blindly be mixed together.

^{Source: Porting Python 2 Code to Python 3}

If we know what version of Python is being used, we can specify the encoding as unicode or utf-8. Otherwise, if we need compatibility with both Python 2 & 3, we can use decode() to convert into the correct type.

For reference, I've included a comparison of .tostring() results between Python 2 and Python 3.

ElementTree.tostring(xml)
# Python 3: b'<Person Name="John" />'
# Python 2: <Person Name="John" />

ElementTree.tostring(xml, encoding='unicode')
# Python 3: <Person Name="John" />
# Python 2: LookupError: unknown encoding: unicode

ElementTree.tostring(xml, encoding='utf-8')
# Python 3: b'<Person Name="John" />'
# Python 2: <Person Name="John" />

ElementTree.tostring(xml).decode()
# Python 3: <Person Name="John" />
# Python 2: <Person Name="John" />

Thanks to Martijn Peters for pointing out that the str datatype changed between Python 2 and 3.

Why not use str()?

In most scenarios, using str() would be the "cannonical" way to convert an object to a string. Unfortunately, using this with Element returns the object's location in memory as a hexstring, rather than a string representation of the object's data.

from xml.etree import ElementTree

xml = ElementTree.Element("Person", Name="John")
print(str(xml))  # <Element 'Person' at 0x00497A80>

How do I convert ElementTree.Element to a String?

For Python 3:

xml_str = ElementTree.tostring(xml, encoding='unicode')

For Python 2:

xml_str = ElementTree.tostring(xml, encoding='utf-8')

Example usage (Python 3)

from xml.etree import ElementTree

xml = ElementTree.Element("Person", Name="John")
xml_str = ElementTree.tostring(xml, encoding='unicode')
print(xml_str)

Output:

<Person Name="John" />

Explanation

ElementTree.tostring() returns a bytestring by default in Python 2 & 3. This is an issue because Python 3 switched to using Unicode for strings.

In Python 2 you could use the str type for both text and binary data. Unfortunately this confluence of two different concepts could lead to brittle code which sometimes worked for either kind of data, sometimes not. [...]

To make the distinction between text and binary data clearer and more pronounced, [Python 3] made text and binary data distinct types that cannot blindly be mixed together.

^{Source: Porting Python 2 Code to Python 3}

If you know what version of Python is being used, you should specify the encoding as unicode or utf-8. For reference, I've included a comparison of .tostring() results between Python 2 and Python 3.

ElementTree.tostring(xml)
# Python 3: b'<Person Name="John" />'
# Python 2: <Person Name="John" />

ElementTree.tostring(xml, encoding='unicode')
# Python 3: <Person Name="John" />
# Python 2: LookupError: unknown encoding: unicode

ElementTree.tostring(xml, encoding='utf-8')
# Python 3: b'<Person Name="John" />'
# Python 2: <Person Name="John" />

ElementTree.tostring(xml).decode()
# Python 3: <Person Name="John" />
# Python 2: <Person Name="John" />

^{Note: While xml_str = ElementTree.tostring().decode() is compatible with both Python 2 & 3, Christopher Rucinski pointed out that this method fails when dealing with non-Latin characters).}

Thanks to Martijn Peters for pointing out that the str datatype changed between Python 2 and 3.

Why not use str()?

In most scenarios, using str() would be the "canonical" way to convert an object to a string. However, using str() with Element returns the object's location in memory as a hexstring, rather than a string representation of the object's data.

from xml.etree import ElementTree

xml = ElementTree.Element("Person", Name="John")
print(str(xml))  # <Element 'Person' at 0x00497A80>