Pretty printing XML in Python

问题

What is the best way (or are the various ways) to pretty print XML in Python?

回答1:

import xml.dom.minidom

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

回答2:

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

回答3:

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)

回答4:

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.

回答5:

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')

回答6:

BeautifulSoup has a easy to use prettify() method.

It indents one space per indentation level. It works much better than lxml's pretty_print and is short and sweet.

from bs4 import BeautifulSoup

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

回答7:

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 += '  '

回答8:

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))

回答9:

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.

回答10:

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')

回答11:

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.

回答12:

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.

回答13:

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

回答14:

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.

回答15:

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') 

回答16:

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.

回答17:

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.

回答18:

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.

回答19:

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!

回答20:

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 :)

回答21:

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').prettify())  

来源：https://stackoverflow.com/questions/749796/pretty-printing-xml-in-python