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I can't read an XML file

It's my first time working with XML files, yet I have a problem with a code as simple as:
from xml.etree import ElementTree as ET
tree = ET.parse('some_xml_file.xml')
s = ET.tostring(tree, method = 'xml')
root = tree.getroot()
all I am trying to do here is reading the XML file as a string,
but whenever I try to run this I get an error:
AttributeError: 'ElementTree' object has no attribute 'tag'
I have no idea what I did wrong just yet, so I would need any hint
and thanks in advance

You can't use ET.tostring on the full tree; you can use it on the root element.
from xml.etree import ElementTree as ET
tree = ET.parse('some_xml_file.xml')
s = ET.tostring(tree.getroot(), method='xml')

How to write Element Tree dump into file

I am try to write the xml dump into the another file. Here is my python code
import xml.etree.ElementTree as ET
tree = ET.parse('extract_orginal.xml')
root = tree.getroot()
with open('extract.xml', 'w') as extract:
for item in root.findall(f"doc[#id='289e1292134534']"):
extract.write(ET.dump(item))
Getting the output as "NONE" in the extract.xml file. Can you please help me.

From the docs of .dump():
"Write element tree or element structure to sys.stdout. This function should be used for debugging only."
The function .dump() returns None!
I think you want to use .tostring():
import xml.etree.ElementTree as ET
tree = ET.parse('extract_orginal.xml')
root = tree.getroot()
with open('extract.xml', 'w') as extract:
for item in root.findall(f"doc[#id='289e1292134534']"):
extract.write(ET.tostring(item, encoding="utf-8"))

Write edited xml that replaced hypen with underscore

So I am trying to write a new xml file that I edited from the original by replacing the hyphen with an underscore and then start working on that xml file for the rest of the code.
This is my code:
import xml.etree.ElementTree as ET
from lxml import etree
#attaching xml file
xmlfile = "hook_zap.xml"
tree = ET.parse(xmlfile)
root = tree.getroot()
#replace hypen with underscore within the xml
doc = etree.parse(xmlfile)
for e in doc.xpath('//*[contains(local-name(),"-")]'):
e.tag = e.tag.replace('-','_')
refracted = etree.tostring(doc, method='xml')
#create a new xml file with refracted file
refracted.write('base.xml')
#print (refracted)
And I keep getting this error:
AttributeError: 'bytes' object has no attribute 'write'

Write refracted like any other kind data into a file:
with open('base.xml', 'w') as f:
f.write(refracted.decode('utf-8'))

I want to append an element to xml’s lead [duplicate]

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.
from xml.etree.ElementTree import Element, tostring
document = Element('outer')
node = SubElement(document, 'inner')
node.NewValue = 1
print tostring(document) # Outputs "<outer><inner /></outer>"
I need my string to include the following XML declaration:
<?xml version="1.0" encoding="UTF-8" standalone="yes" ?>
However, there does not seem to be any documented way of doing this.
Is there a proper method for rendering the XML declaration in an ElementTree?

I am surprised to find that there doesn't seem to be a way with ElementTree.tostring(). You can however use ElementTree.ElementTree.write() to write your XML document to a fake file:
from io import BytesIO
from xml.etree import ElementTree as ET
document = ET.Element('outer')
node = ET.SubElement(document, 'inner')
et = ET.ElementTree(document)
f = BytesIO()
et.write(f, encoding='utf-8', xml_declaration=True)
print(f.getvalue()) # your XML file, encoded as UTF-8
See this question. Even then, I don't think you can get your 'standalone' attribute without writing prepending it yourself.

I would use lxml (see http://lxml.de/api.html).
Then you can:
from lxml import etree
document = etree.Element('outer')
node = etree.SubElement(document, 'inner')
print(etree.tostring(document, xml_declaration=True))

If you include the encoding='utf8', you will get an XML header:
xml.etree.ElementTree.tostring writes a XML encoding declaration with encoding='utf8'
Sample Python code (works with Python 2 and 3):
import xml.etree.ElementTree as ElementTree
tree = ElementTree.ElementTree(
ElementTree.fromstring('<xml><test>123</test></xml>')
)
root = tree.getroot()
print('without:')
print(ElementTree.tostring(root, method='xml'))
print('')
print('with:')
print(ElementTree.tostring(root, encoding='utf8', method='xml'))
Python 2 output:
$ python2 example.py
without:
<xml><test>123</test></xml>
with:
<?xml version='1.0' encoding='utf8'?>
<xml><test>123</test></xml>
With Python 3 you will note the b prefix indicating byte literals are returned (just like with Python 2):
$ python3 example.py
without:
b'<xml><test>123</test></xml>'
with:
b"<?xml version='1.0' encoding='utf8'?>\n<xml><test>123</test></xml>"

xml_declaration Argument
Is there a proper method for rendering the XML declaration in an ElementTree?
YES, and there is no need of using .tostring function. According to ElementTree Documentation, you should create an ElementTree object, create Element and SubElements, set the tree's root, and finally use xml_declaration argument in .write function, so the declaration line is included in output file.
You can do it this way:
import xml.etree.ElementTree as ET
tree = ET.ElementTree("tree")
document = ET.Element("outer")
node1 = ET.SubElement(document, "inner")
node1.text = "text"
tree._setroot(document)
tree.write("./output.xml", encoding = "UTF-8", xml_declaration = True)
And the output file is:
<?xml version='1.0' encoding='UTF-8'?>
<outer><inner>text</inner></outer>

I encounter this issue recently, after some digging of the code, I found the following code snippet is definition of function ElementTree.write
def write(self, file, encoding="us-ascii"):
assert self._root is not None
if not hasattr(file, "write"):
file = open(file, "wb")
if not encoding:
encoding = "us-ascii"
elif encoding != "utf-8" and encoding != "us-ascii":
file.write("<?xml version='1.0' encoding='%s'?>\n" %
encoding)
self._write(file, self._root, encoding, {})
So the answer is, if you need write the XML header to your file, set the encoding argument other than utf-8 or us-ascii, e.g. UTF-8

Easy
Sample for both Python 2 and 3 (encoding parameter must be utf8):
import xml.etree.ElementTree as ElementTree
tree = ElementTree.ElementTree(ElementTree.fromstring('<xml><test>123</test></xml>'))
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('<xml><test>123</test></xml>'))
root = tree.getroot()
print(ElementTree.tostring(root, encoding='unicode', method='xml', xml_declaration=True))

The minimal working example with ElementTree package usage:
import xml.etree.ElementTree as ET
document = ET.Element('outer')
node = ET.SubElement(document, 'inner')
node.text = '1'
res = ET.tostring(document, encoding='utf8', method='xml').decode()
print(res)
the output is:
<?xml version='1.0' encoding='utf8'?>
<outer><inner>1</inner></outer>

Another pretty simple option is to concatenate the desired header to the string of xml like this:
xml = (bytes('<?xml version="1.0" encoding="UTF-8"?>\n', encoding='utf-8') + ET.tostring(root))
xml = xml.decode('utf-8')
with open('invoice.xml', 'w+') as f:
f.write(xml)

I would use ET:
try:
from lxml import etree
print("running with lxml.etree")
except ImportError:
try:
# Python 2.5
import xml.etree.cElementTree as etree
print("running with cElementTree on Python 2.5+")
except ImportError:
try:
# Python 2.5
import xml.etree.ElementTree as etree
print("running with ElementTree on Python 2.5+")
except ImportError:
try:
# normal cElementTree install
import cElementTree as etree
print("running with cElementTree")
except ImportError:
try:
# normal ElementTree install
import elementtree.ElementTree as etree
print("running with ElementTree")
except ImportError:
print("Failed to import ElementTree from any known place")
document = etree.Element('outer')
node = etree.SubElement(document, 'inner')
print(etree.tostring(document, encoding='UTF-8', xml_declaration=True))

This works if you just want to print. Getting an error when I try to send it to a file...
import xml.dom.minidom as minidom
import xml.etree.ElementTree as ET
from xml.etree.ElementTree import Element, SubElement, Comment, tostring
def prettify(elem):
rough_string = ET.tostring(elem, 'utf-8')
reparsed = minidom.parseString(rough_string)
return reparsed.toprettyxml(indent=" ")

Including 'standalone' in the declaration
I didn't found any alternative for adding the standalone argument in the documentation so I adapted the ET.tosting function to take it as an argument.
from xml.etree import ElementTree as ET
# Sample
document = ET.Element('outer')
node = ET.SubElement(document, 'inner')
et = ET.ElementTree(document)
# Function that you need
def tostring(element, declaration, encoding=None, method=None,):
class dummy:
pass
data = []
data.append(declaration+"\n")
file = dummy()
file.write = data.append
ET.ElementTree(element).write(file, encoding, method=method)
return "".join(data)
# Working example
xdec = """<?xml version="1.0" encoding="UTF-8" standalone="no" ?>"""
xml = tostring(document, encoding='utf-8', declaration=xdec)

Parsing an xml file and creating another from the parsed object

I am trying to parse an xml file(containing bad characters) using lxml module in recover = True mode.
Below is the code snippet
from lxml import etree
f=open('test.xml')
data=f.read()
f.close()
parser = etree.XMLParser(recover=True)
x = etree.fromstring(data, parser=parser)
Now I want to create another xml file (test1.xml) from the above object (x)
Could anyone please help in this matter.
Thanks

I think this is what you are searching for
from lxml import etree
# opening the source file
with open('test.xml','r') as f:
# reading the number
data=f.read()
parser = etree.XMLParser(recover=True)
# fromstring() parses XML from a string directly into an Element
x = etree.fromstring(data, parser=parser)
# taking the content retrieved
y = etree.tostring(x, pretty_print=True).decode("utf-8")
# writing the content on the output file
with open('test1.xml','w') as f:
f.write(y)