Pretty printing XML in Python

p

pj.dewitte

import xml.dom.minidom

dom = xml.dom.minidom.parse(xml_fname) # or xml.dom.minidom.parseString(xml_string)
pretty_xml_as_string = dom.toprettyxml()

This will get you pretty xml, but note that what comes out in the text node is actually different than what came in - there are new whitespaces on text nodes. This may cause you trouble if you are expecting EXACTLY what fed in to feed out.

@icnivad: while it is important to point that fact, it seems strange to me that somebody would want to prettify its XML if spaces were of some importance for them !

Nice! Can collapse this to a one liner: python -c 'import sys;import xml.dom.minidom;s=sys.stdin.read();print xml.dom.minidom.parseString(s).toprettyxml()'

minidom is widely panned as a pretty bad xml implementation. If you allow yourself to add external depenencies, lxml is far superior.

Not a fan of redefining xml there from being a module to the output object, but the method otherwise works. I'd love to find a nicer way to go from the core etree to pretty printing. While lxml is cool, there are times when I'd prefer to keep to the core if I can.

M

Mad Physicist

lxml is recent, updated, and includes a pretty print function

import lxml.etree as etree

x = etree.parse("filename")
print etree.tostring(x, pretty_print=True)

Check out the lxml tutorial: http://lxml.de/tutorial.html

Only downside to lxml is a dependency on external libraries. This I think is not so bad under Windows the libraries are packaged with the module. Under linux they are an aptitude install away. Under OS/X I'm not sure.

On OS X you just need a functioning gcc and easy_install/pip.

lxml pretty printer isn't reliable and won't pretty print your XML properly in lots of cases explained in lxml FAQ. I quit using lxml for pretty printing after several corner cases that just don't work (ie this won't fix: Bug #910018). All these problem is related to uses of XML values containing spaces that should be preserved.

Since in Python 3 you usually want to work with str (=unicode string in Python 2), better use this: print(etree.tostring(x, pretty_print=True, encoding="unicode")). Writing to an output file is possible in just one line, no intermediary variable needed: etree.parse("filename").write("outputfile", encoding="utf-8")

etree.XMLParser(remove_blank_text=True) sometime can help to do the right printing

J

Jimmy.Rustle

Another solution is to borrow this indent function, for use with the ElementTree library that's built in to Python since 2.5. Here's what that would look like:

from xml.etree import ElementTree

def indent(elem, level=0):
    i = "\n" + level*"  "
    j = "\n" + (level-1)*"  "
    if len(elem):
        if not elem.text or not elem.text.strip():
            elem.text = i + "  "
        if not elem.tail or not elem.tail.strip():
            elem.tail = i
        for subelem in elem:
            indent(subelem, level+1)
        if not elem.tail or not elem.tail.strip():
            elem.tail = j
    else:
        if level and (not elem.tail or not elem.tail.strip()):
            elem.tail = j
    return elem        

root = ElementTree.parse('/tmp/xmlfile').getroot()
indent(root)
ElementTree.dump(root)

...and then just use lxml tostring!

Note that you can still do tree.write([filename]) for writing to file (tree being the ElementTree instance).

This link effbot.org/zone/element-lib.htm#prettyprint has the right code. The code here has something wrong. Need to be edited.

No you can't since elementtree.getroot() doesn't have that method, only an elementtree object has it. @bouke

Here's how you can write to a file: tree = ElementTree.parse('file) ; root = tree.getroot() ; indent(root); tree.write('Out.xml');

C

ChaimG

You have a few options.

xml.etree.ElementTree.indent()

Batteries included, simple to use, pretty output.

But requires Python 3.9+

import xml.etree.ElementTree as ET

element = ET.XML("<html><body>text</body></html>")
ET.indent(element)
print(ET.tostring(element, encoding='unicode'))

BeautifulSoup.prettify()

BeautifulSoup may be the simplest solution for Python < 3.9.

from bs4 import BeautifulSoup

bs = BeautifulSoup(open(xml_file), 'xml')
pretty_xml = bs.prettify()
print(pretty_xml)

Output:

1 Add Visual Studio 2005 and 2008 solution files

This is my goto answer. The default arguments work as is. But text contents are spread out on separate lines as if they were nested elements.

lxml.etree.parse()

Prettier output but with arguments.

from lxml import etree

x = etree.parse(FILE_NAME)
pretty_xml = etree.tostring(x, pretty_print=True, encoding=str)

Produces:

1 Add Visual Studio 2005 and 2008 solution files

We need Visual Studio 2005/2008 project files for Windows.

This works for me with no issues.

xml.dom.minidom.parse()

No external dependencies but post-processing.

import xml.dom.minidom as md

dom = md.parse(FILE_NAME)     
# To parse string instead use: dom = md.parseString(xml_string)
pretty_xml = dom.toprettyxml()
# remove the weird newline issue:
pretty_xml = os.linesep.join([s for s in pretty_xml.splitlines()
                              if s.strip()])

The output is the same as above, but it's more code.

Getting this error message:

bs4.FeatureNotFound: Couldn't find a tree builder with the features you requested: xml. Do you need to install a parser library?

You need to run python3 -m pip install --user lxml

Good job man :) for remove the weird newline issue ! ty

N

Nick Bolton

Here's my (hacky?) solution to get around the ugly text node problem.

uglyXml = doc.toprettyxml(indent='  ')

text_re = re.compile('>\n\s+([^<>\s].*?)\n\s+</', re.DOTALL)    
prettyXml = text_re.sub('>\g<1></', uglyXml)

print prettyXml

The above code will produce:

<?xml version="1.0" ?>
<issues>
  <issue>
    <id>1</id>
    <title>Add Visual Studio 2005 and 2008 solution files</title>
    <details>We need Visual Studio 2005/2008 project files for Windows.</details>
  </issue>
</issues>

Instead of this:

<?xml version="1.0" ?>
<issues>
  <issue>
    <id>
      1
    </id>
    <title>
      Add Visual Studio 2005 and 2008 solution files
    </title>
    <details>
      We need Visual Studio 2005/2008 project files for Windows.
    </details>
  </issue>
</issues>

Disclaimer: There are probably some limitations.

Thank you! This was my one gripe with all the pretty printing methods. Works well with the few files I tried.

I found a pretty 'almost identical' solution, but yours is more direct, using re.compile prior to sub operation (I was using re.findall() twice, zip and a for loop with str.replace()...)

This is no longer necessary in Python 2.7: xml.dom.minidom's toprettyxml() now produces output like '1' by default, for nodes that have exactly one text child node.

I am compelled to use Python 2.6. So, this regex reformatting trick is very useful. Worked as-is with no problems.

@Marius Gedminas I am running 2.7.2 and the "default" is definitely not as you say.

m

mzjn

As of Python 3.9, ElementTree has an indent() function for pretty-printing XML trees.

See https://docs.python.org/3/library/xml.etree.elementtree.html#xml.etree.ElementTree.indent.

Sample usage:

import xml.etree.ElementTree as ET

element = ET.XML("<html><body>text</body></html>")
ET.indent(element)
print(ET.tostring(element, encoding='unicode'))

The upside is that it does not require any additional libraries. For more information check https://bugs.python.org/issue14465 and https://github.com/python/cpython/pull/15200

r

roskakori

As others pointed out, lxml has a pretty printer built in.

Be aware though that by default it changes CDATA sections to normal text, which can have nasty results.

Here's a Python function that preserves the input file and only changes the indentation (notice the strip_cdata=False). Furthermore it makes sure the output uses UTF-8 as encoding instead of the default ASCII (notice the encoding='utf-8'):

from lxml import etree

def prettyPrintXml(xmlFilePathToPrettyPrint):
    assert xmlFilePathToPrettyPrint is not None
    parser = etree.XMLParser(resolve_entities=False, strip_cdata=False)
    document = etree.parse(xmlFilePathToPrettyPrint, parser)
    document.write(xmlFilePathToPrettyPrint, pretty_print=True, encoding='utf-8')

Example usage:

prettyPrintXml('some_folder/some_file.xml')

It's a little late now. But I think lxml fixed CDATA? CDATA is CDATA on my side.

R

Russell Silva

If you have xmllint you can spawn a subprocess and use it. xmllint --format <file> pretty-prints its input XML to standard output.

Note that this method uses an program external to python, which makes it sort of a hack.

def pretty_print_xml(xml):
    proc = subprocess.Popen(
        ['xmllint', '--format', '/dev/stdin'],
        stdin=subprocess.PIPE,
        stdout=subprocess.PIPE,
    )
    (output, error_output) = proc.communicate(xml);
    return output

print(pretty_print_xml(data))

R

Rónán Daly

I tried to edit "ade"s answer above, but Stack Overflow wouldn't let me edit after I had initially provided feedback anonymously. This is a less buggy version of the function to pretty-print an ElementTree.

def indent(elem, level=0, more_sibs=False):
    i = "\n"
    if level:
        i += (level-1) * '  '
    num_kids = len(elem)
    if num_kids:
        if not elem.text or not elem.text.strip():
            elem.text = i + "  "
            if level:
                elem.text += '  '
        count = 0
        for kid in elem:
            indent(kid, level+1, count < num_kids - 1)
            count += 1
        if not elem.tail or not elem.tail.strip():
            elem.tail = i
            if more_sibs:
                elem.tail += '  '
    else:
        if level and (not elem.tail or not elem.tail.strip()):
            elem.tail = i
            if more_sibs:
                elem.tail += '  '

b

bobince

If you're using a DOM implementation, each has their own form of pretty-printing built-in:

# minidom
#
document.toprettyxml()

# 4DOM
#
xml.dom.ext.PrettyPrint(document, stream)

# pxdom (or other DOM Level 3 LS-compliant imp)
#
serializer.domConfig.setParameter('format-pretty-print', True)
serializer.writeToString(document)

If you're using something else without its own pretty-printer — or those pretty-printers don't quite do it the way you want — you'd probably have to write or subclass your own serialiser.

g

giltay

I had some problems with minidom's pretty print. I'd get a UnicodeError whenever I tried pretty-printing a document with characters outside the given encoding, eg if I had a β in a document and I tried doc.toprettyxml(encoding='latin-1'). Here's my workaround for it:

def toprettyxml(doc, encoding):
    """Return a pretty-printed XML document in a given encoding."""
    unistr = doc.toprettyxml().replace(u'<?xml version="1.0" ?>',
                          u'<?xml version="1.0" encoding="%s"?>' % encoding)
    return unistr.encode(encoding, 'xmlcharrefreplace')

J

John Smith Optional

from yattag import indent

pretty_string = indent(ugly_string)

It won't add spaces or newlines inside text nodes, unless you ask for it with:

indent(mystring, indent_text = True)

You can specify what the indentation unit should be and what the newline should look like.

pretty_xml_string = indent(
    ugly_xml_string,
    indentation = '    ',
    newline = '\r\n'
)

The doc is on http://www.yattag.org homepage.

n

nacitar sevaht

I wrote a solution to walk through an existing ElementTree and use text/tail to indent it as one typically expects.

def prettify(element, indent='  '):
    queue = [(0, element)]  # (level, element)
    while queue:
        level, element = queue.pop(0)
        children = [(level + 1, child) for child in list(element)]
        if children:
            element.text = '\n' + indent * (level+1)  # for child open
        if queue:
            element.tail = '\n' + indent * queue[0][0]  # for sibling open
        else:
            element.tail = '\n' + indent * (level-1)  # for parent close
        queue[0:0] = children  # prepend so children come before siblings

J

Josh Correia

Here's a Python3 solution that gets rid of the ugly newline issue (tons of whitespace), and it only uses standard libraries unlike most other implementations.

import xml.etree.ElementTree as ET
import xml.dom.minidom
import os

def pretty_print_xml_given_root(root, output_xml):
    """
    Useful for when you are editing xml data on the fly
    """
    xml_string = xml.dom.minidom.parseString(ET.tostring(root)).toprettyxml()
    xml_string = os.linesep.join([s for s in xml_string.splitlines() if s.strip()]) # remove the weird newline issue
    with open(output_xml, "w") as file_out:
        file_out.write(xml_string)

def pretty_print_xml_given_file(input_xml, output_xml):
    """
    Useful for when you want to reformat an already existing xml file
    """
    tree = ET.parse(input_xml)
    root = tree.getroot()
    pretty_print_xml_given_root(root, output_xml)

I found how to fix the common newline issue here.

D

Dan Lew

XML pretty print for python looks pretty good for this task. (Appropriately named, too.)

An alternative is to use pyXML, which has a PrettyPrint function.

HTTPError: 404 Client Error: Not Found for url: https://pypi.org/simple/xmlpp/ Think that project is in the attic nowadays, shame.

V

Vitaly Zdanevich

You can use popular external library xmltodict, with unparse and pretty=True you will get best result:

xmltodict.unparse(
    xmltodict.parse(my_xml), full_document=False, pretty=True)

full_document=False against <?xml version="1.0" encoding="UTF-8"?> at the top.

v

vadimk

Take a look at the vkbeautify module.

It is a python version of my very popular javascript/nodejs plugin with the same name. It can pretty-print/minify XML, JSON and CSS text. Input and output can be string/file in any combinations. It is very compact and doesn't have any dependency.

Examples:

import vkbeautify as vkb

vkb.xml(text)                       
vkb.xml(text, 'path/to/dest/file')  
vkb.xml('path/to/src/file')        
vkb.xml('path/to/src/file', 'path/to/dest/file')

This particular library handles the Ugly Text Node problem.

N

NYCeyes

You can try this variation...

Install BeautifulSoup and the backend lxml (parser) libraries:

user$ pip3 install lxml bs4

Process your XML document:

from bs4 import BeautifulSoup

with open('/path/to/file.xml', 'r') as doc: 
    for line in doc: 
        print(BeautifulSoup(line, 'lxml-xml').prettify())

'lxml' uses lxml's HTML parser - see the BS4 docs. You need 'xml' or 'lxml-xml' for the XML parser.

This comment keeps getting deleted. Again, I've enter a formal complaint (in addition to) 4-flags) of post tampering with StackOverflow, and will not stop until this is forensically investigated by a security team (access logs and version histories). The above timestamp is wrong (by years) and likely the content, too.

This worked fine for me, unsure of the down vote from the docs lxml’s XML parser BeautifulSoup(markup, "lxml-xml") BeautifulSoup(markup, "xml")

@Datanovice I'm glad it helped you. :) As for the suspect downvote, someone tampered with my original answer (which correctly originally specified lxml-xml), and then they proceeded to downvote it that same day. I submitted an official complaint to S/O but they refused to investigate. Anyway, I have since "de-tampered" my answer, which is now correct again (and specifies lxml-xml as it originally did). Thank you.

g

gaborous

An alternative if you don't want to have to reparse, there is the xmlpp.py library with the get_pprint() function. It worked nice and smoothly for my use cases, without having to reparse to an lxml ElementTree object.

Tried minidom and lxml and didn't get a properly formatted and indented xml. This worked as expected

Fails for tag names that are prefixed by a namespace and contain a hyphen (e.g. ; the part starting with the hyphen is simply dropped, giving e.g. .

@EndreBoth Nice catch, I did not test, but maybe it would be easy to fix this in the xmlpp.py code?

Z

Zelphir Kaltstahl

I had this problem and solved it like this:

def write_xml_file (self, file, xml_root_element, xml_declaration=False, pretty_print=False, encoding='unicode', indent='\t'):
    pretty_printed_xml = etree.tostring(xml_root_element, xml_declaration=xml_declaration, pretty_print=pretty_print, encoding=encoding)
    if pretty_print: pretty_printed_xml = pretty_printed_xml.replace('  ', indent)
    file.write(pretty_printed_xml)

In my code this method is called like this:

try:
    with open(file_path, 'w') as file:
        file.write('<?xml version="1.0" encoding="utf-8" ?>')

        # create some xml content using etree ...

        xml_parser = XMLParser()
        xml_parser.write_xml_file(file, xml_root, xml_declaration=False, pretty_print=True, encoding='unicode', indent='\t')

except IOError:
    print("Error while writing in log file!")

This works only because etree by default uses two spaces to indent, which I don't find very much emphasizing the indentation and therefore not pretty. I couldn't ind any setting for etree or parameter for any function to change the standard etree indent. I like how easy it is to use etree, but this was really annoying me.

G

Gabriel Staples

For converting an entire xml document to a pretty xml document
(ex: assuming you've extracted [unzipped] a LibreOffice Writer .odt or .ods file, and you want to convert the ugly "content.xml" file to a pretty one for automated git version control and git difftooling of .odt/.ods files, such as I'm implementing here)

import xml.dom.minidom

file = open("./content.xml", 'r')
xml_string = file.read()
file.close()

parsed_xml = xml.dom.minidom.parseString(xml_string)
pretty_xml_as_string = parsed_xml.toprettyxml()

file = open("./content_new.xml", 'w')
file.write(pretty_xml_as_string)
file.close()

References:
- Thanks to Ben Noland's answer on this page which got me most of the way there.

R

Reed_Xia

from lxml import etree
import xml.dom.minidom as mmd

xml_root = etree.parse(xml_fiel_path, etree.XMLParser())

def print_xml(xml_root):
    plain_xml = etree.tostring(xml_root).decode('utf-8')
    urgly_xml = ''.join(plain_xml .split())
    good_xml = mmd.parseString(urgly_xml)
    print(good_xml.toprettyxml(indent='    ',))

It's working well for the xml with Chinese!

F

FriskySaga

If for some reason you can't get your hands on any of the Python modules that other users mentioned, I suggest the following solution for Python 2.7:

import subprocess

def makePretty(filepath):
  cmd = "xmllint --format " + filepath
  prettyXML = subprocess.check_output(cmd, shell = True)
  with open(filepath, "w") as outfile:
    outfile.write(prettyXML)

As far as I know, this solution will work on Unix-based systems that have the xmllint package installed.

xmllint has already been suggested in another answer: stackoverflow.com/a/10133365/407651

@mzjn I saw the answer, but I simplified mine down to check_output because you don't need to do error checking

e

emehex

I found this question while looking for "how to pretty print html"

Using some of the ideas in this thread I adapted the XML solutions to work for XML or HTML:

from xml.dom.minidom import parseString as string_to_dom

def prettify(string, html=True):
    dom = string_to_dom(string)
    ugly = dom.toprettyxml(indent="  ")
    split = list(filter(lambda x: len(x.strip()), ugly.split('\n')))
    if html:
        split = split[1:]
    pretty = '\n'.join(split)
    return pretty

def pretty_print(html):
    print(prettify(html))

When used this is what it looks like:

html = """\
<div class="foo" id="bar"><p>'IDK!'</p><br/><div class='baz'><div>
<span>Hi</span></div></div><p id='blarg'>Try for 2</p>
<div class='baz'>Oh No!</div></div>
"""

pretty_print(html)

Which returns:

<div class="foo" id="bar">
  <p>'IDK!'</p>
  <br/>
  <div class="baz">
    <div>
      <span>Hi</span>
    </div>
  </div>
  <p id="blarg">Try for 2</p>
  <div class="baz">Oh No!</div>
</div>

J

Jossef Harush Kadouri

Use etree.indent and etree.tostring

import lxml.etree as etree

root = etree.fromstring('<html><head></head><body><h1>Welcome</h1></body></html>')
etree.indent(root, space="  ")
xml_string = etree.tostring(root, pretty_print=True).decode()
print(xml_string)

output

<html>
  <head/>
  <body>
    <h1>Welcome</h1>
  </body>
</html>

Removing namespaces and prefixes

import lxml.etree as etree


def dump_xml(element):
    for item in element.getiterator():
        item.tag = etree.QName(item).localname

    etree.cleanup_namespaces(element)
    etree.indent(element, space="  ")
    result = etree.tostring(element, pretty_print=True).decode()
    return result


root = etree.fromstring('<cs:document xmlns:cs="http://blabla.com"><name>hello world</name></cs:document>')
xml_string = dump_xml(root)
print(xml_string)

output

<document>
  <name>hello world</name>
</document>

W

Wuagliono

I found a fast and easy way to nicely format and print an xml file:

import xml.etree.ElementTree as ET

xmlTree = ET.parse('your XML file')
xmlRoot = xmlTree.getroot()
xmlDoc =  ET.tostring(xmlRoot, encoding="unicode")

print(xmlDoc)

Outuput:

<root>
  <child>
    <subchild>.....</subchild>
  </child>
  <child>
    <subchild>.....</subchild>
  </child>
  ...
  ...
  ...
  <child>
    <subchild>.....</subchild>
  </child>
</root>

P

Petter TB

I solved this with some lines of code, opening the file, going trough it and adding indentation, then saving it again. I was working with small xml files, and did not want to add dependencies, or more libraries to install for the user. Anyway, here is what I ended up with:

    f = open(file_name,'r')
    xml = f.read()
    f.close()

    #Removing old indendations
    raw_xml = ''        
    for line in xml:
        raw_xml += line

    xml = raw_xml

    new_xml = ''
    indent = '    '
    deepness = 0

    for i in range((len(xml))):

        new_xml += xml[i]   
        if(i<len(xml)-3):

            simpleSplit = xml[i:(i+2)] == '><'
            advancSplit = xml[i:(i+3)] == '></'        
            end = xml[i:(i+2)] == '/>'    
            start = xml[i] == '<'

            if(advancSplit):
                deepness += -1
                new_xml += '\n' + indent*deepness
                simpleSplit = False
                deepness += -1
            if(simpleSplit):
                new_xml += '\n' + indent*deepness
            if(start):
                deepness += 1
            if(end):
                deepness += -1

    f = open(file_name,'w')
    f.write(new_xml)
    f.close()

It works for me, perhaps someone will have some use of it :)

Pretty printing XML in Python

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