import xml.etree.ElementTree as ET
def addCommentInXml():
fileXml ='C:\\Users\\Documents\\config.xml'
tree = ET.parse(fileXml)
root = tree.getroot()
comment = ET.Comment('TEST')
root.insert(1, comment) # 1 is the index where comment is inserted
tree.write(fileXml, encoding='UTF-8', xml_declaration=True)
print("Done")
It is updating xml as below,Please suggest how to add right after xml declaration line:
<?xml version='1.0' encoding='UTF-8'?>
<ScopeConfig Checksum="5846AFCF4E5D02786">
<ExecutableName>STU</ExecutableName>
<!--TEST--><ZoomT2Encoder>-2230</ZoomT2Encoder>
The ElementTree XML API does not allow this. The documentation for the Comment factory function explicitly states:
An ElementTree will only contain comment nodes if they have been
inserted into to the tree using one of the Element methods.
but you would like to insert a comment outside the tree. The documentation for the TreeBuilder class is even more explicit:
When insert_comments and/or insert_pis is true, comments/pis will be
inserted into the tree if they appear within the root element (but not
outside of it)
So I would suggest writing out the XML file without the comment, using this API, and then reading the file as plain text (not parsed XML) to add your comment after the first line.
I am trying to read xml behind an spss file, I would like to move from etree to objectify.
How can I convert this function below to return an objectify object? I would like to do this because objectify xml object would be easier for me (as a newbie) to work with as it is more pythonic.
def get_etree(path_file):
from lxml import etree
with open(path_file, 'r+') as f:
xml_text = f.read()
recovering_parser = etree.XMLParser(recover=True)
xml = etree.parse(StringIO(xml_text), parser=recovering_parser)
return xml
my failed attempt:
def get_etree(path_file):
from lxml import etree, objectify
with open(path_file, 'r+') as f:
xml_text = objectify.fromstring(xml)
return xml
but I get this error:
lxml.etree.XMLSyntaxError: xmlns:mdm: 'http://www.spss.com/mr/dm/metadatamodel/Arc 3/2000-02-04' is not a valid URI
The first, biggest mistake is to read a file into a string and feed that string to an XML parser.
Python will read the file as whatever your default file encoding is (unless you specify the encoding when you call read()), and that step will very likely break anything other than plain ASCII files.
XML files come in many encodings, you cannot predict them, and you really shouldn't make assumptions about them. XML files solve that problem with the XML declaration.
<?xml version="1.0" encoding="Windows-1252"?>
An XML parser will read that bit of information and configure itself correctly before reading the rest of the file. Make use of that facility. Never use open() and read() for XML files.
Luckily lxml makes it very easy:
from lxml import etree, objectify
def get_etree(path_file):
return etree.parse(path_file, parser=etree.XMLParser(recover=True))
def get_objectify(path_file):
return objectify.parse(path_file)
and
path = r"/path/to/your.xml"
xml1 = get_etree(path)
xml2 = get_objectify(path)
print xml1 # -> <lxml.etree._ElementTree object at 0x02A7B918>
print xml2 # -> <lxml.etree._ElementTree object at 0x02A7B878>
P.S.: Think hard if you really, positively must use a recovering parser. An XML file is a data structure. If it is broken (syntactically invalid, incomplete, wrongly decoded, you name it), would you really want to trust the (by definition undefined) result of an attempt to read it anyway or would you much rather reject it and display an error message?
I would do the latter. Using a recovering parser may cause nasty run-time errors later.
I'm working on a project to store various bits of text in xml files, but because people besides me are going to look at it and use it, it has to be properly indented and such. I looked at a question on how to generate xml files using cElement Tree here, and the guy says something about putting in info about making things pretty if people ask, but there isn't anything there (I guess because no one asked). So basically, is there a way to properly indent and whitespace using cElementTree, or should i just throw up my hands and go learn how to use lxml.
You can use minidom to prettify our xml string:
from xml.etree import ElementTree as ET
from xml.dom import minidom
# Return a pretty-printed XML string for the Element.
def prettify(xmlStr):
INDENT = " "
rough_string = ET.tostring(xmlStr, 'utf-8')
reparsed = minidom.parseString(rough_string)
return reparsed.toprettyxml(indent=INDENT)
# name of root tag
root = ET.Element("root")
child = ET.SubElement(root, 'child')
child.text = 'This is text of child'
prettified_xmlStr = prettify(root)
output_file = open("Output.xml", "w")
output_file.write(prettified_xmlStr)
output_file.close()
print("Done!")
Answering myself here:
Not with ElementTree. The best option would be to download and install the module for lxml, then simply enable the option
prettyprint = True
when generating new XML files.
I have this little code and it's giving me AttributeError: 'NoneType' object has no attribute 'group'.
import sys
import re
#def extract_names(filename):
f = open('name.html', 'r')
text = f.read()
match = re.search (r'<hgroup><h1>(\w+)</h1>', text)
second = re.search (r'<li class="hover">Employees: <b>(\d+,\d+)</b></li>', text)
outf = open('details.txt', 'a')
outf.write(match)
outf.close()
My intention is to read a .HTML file looking for the <h1> tag value and the number of employees and append them to a file. But for some reason I can't seem to get it right.
Your help is greatly appreciated.
You are using a regular expression, but matching XML with such expressions gets too complicated, too fast. Don't do that.
Use a HTML parser instead, Python has several to choose from:
ElementTree is part of the standard library
BeautifulSoup is a popular 3rd party library
lxml is a fast and feature-rich C-based library.
The latter two handle malformed HTML quite gracefully as well, making decent sense of many a botched website.
ElementTree example:
from xml.etree import ElementTree
tree = ElementTree.parse('filename.html')
for elem in tree.findall('h1'):
print ElementTree.tostring(elem)
Just for the sake of completion: your error message just indicate that your regular expression failed and did not return anything...
I have an XML document that I would like to update after it already contains data.
I thought about opening the XML file in "a" (append) mode. The problem is that the new data will be written after the root closing tag.
How can I delete the last line of a file, then start writing data from that point, and then close the root tag?
Of course I could read the whole file and do some string manipulations, but I don't think that's the best idea..
Using ElementTree:
import xml.etree.ElementTree
# Open original file
et = xml.etree.ElementTree.parse('file.xml')
# Append new tag: <a x='1' y='abc'>body text</a>
new_tag = xml.etree.ElementTree.SubElement(et.getroot(), 'a')
new_tag.text = 'body text'
new_tag.attrib['x'] = '1' # must be str; cannot be an int
new_tag.attrib['y'] = 'abc'
# Write back to file
#et.write('file.xml')
et.write('file_new.xml')
note: output written to file_new.xml for you to experiment, writing back to file.xml will replace the old content.
IMPORTANT: the ElementTree library stores attributes in a dict, as such, the order in which these attributes are listed in the xml text will NOT be preserved. Instead, they will be output in alphabetical order.
(also, comments are removed. I'm finding this rather annoying)
ie: the xml input text <b y='xxx' x='2'>some body</b> will be output as <b x='2' y='xxx'>some body</b>(after alphabetising the order parameters are defined)
This means when committing the original, and changed files to a revision control system (such as SVN, CSV, ClearCase, etc), a diff between the 2 files may not look pretty.
Useful Python XML parsers:
Minidom - functional but limited
ElementTree - decent performance, more functionality
lxml - high-performance in most cases, high functionality including real xpath support
Any of those is better than trying to update the XML file as strings of text.
What that means to you:
Open your file with an XML parser of your choice, find the node you're interested in, replace the value, serialize the file back out.
The quick and easy way, which you definitely should not do (see below), is to read the whole file into a list of strings using readlines(). I write this in case the quick and easy solution is what you're looking for.
Just open the file using open(), then call the readlines() method. What you'll get is a list of all the strings in the file. Now, you can easily add strings before the last element (just add to the list one element before the last). Finally, you can write these back to the file using writelines().
An example might help:
my_file = open(filename, "r")
lines_of_file = my_file.readlines()
lines_of_file.insert(-1, "This line is added one before the last line")
my_file.writelines(lines_of_file)
The reason you shouldn't be doing this is because, unless you are doing something very quick n' dirty, you should be using an XML parser. This is a library that allows you to work with XML intelligently, using concepts like DOM, trees, and nodes. This is not only the proper way to work with XML, it is also the standard way, making your code both more portable, and easier for other programmers to understand.
Tim's answer mentioned checking out xml.dom.minidom for this purpose, which I think would be a great idea.
While I agree with Tim and Oben Sonne that you should use an XML library, there are ways to still manipulate it as a simple string object.
I likely would not try to use a single file pointer for what you are describing, and instead read the file into memory, edit it, then write it out.:
inFile = open('file.xml', 'r')
data = inFile.readlines()
inFile.close()
# some manipulation on `data`
outFile = open('file.xml', 'w')
outFile.writelines(data)
outFile.close()
For the modification, you could use tag.text from xml. Here is snippet:
import xml.etree.ElementTree as ET
tree = ET.parse('country_data.xml')
root = tree.getroot()
for rank in root.iter('rank'):
new_rank = int(rank.text) + 1
rank.text = str(new_rank)
tree.write('output.xml')
The rank in the code is example of tag, which depending on your XML file contents.
What you really want to do is use an XML parser and append the new elements with the API provided.
Then simply overwrite the file.
The easiest to use would probably be a DOM parser like the one below:
http://docs.python.org/library/xml.dom.minidom.html
To make this process more robust, you could consider using the SAX parser (that way you don't have to hold the whole file in memory), read & write till the end of tree and then start appending.
You should read the XML file using specific XML modules. That way you can edit the XML document in memory and rewrite your changed XML document into the file.
Here is a quick start: http://docs.python.org/library/xml.dom.minidom.html
There are a lot of other XML utilities, which one is best depends on the nature of your XML file and in which way you want to edit it.
As Edan Maor explained, the quick and dirty way to do it (for [utc-16] encoded .xml files), which you should not do for the resons Edam Maor explained, can done with the following python 2.7 code in case time constraints do not allow you to learn (propper) XML parses.
Assuming you want to:
Delete the last line in the original xml file.
Add a line
substitute a line
Close the root tag.
It worked in python 2.7 modifying an .xml file named "b.xml" located in folder "a", where "a" was located in the "working folder" of python. It outputs the new modified file as "c.xml" in folder "a", without yielding encoding errors (for me) in further use outside of python 2.7.
pattern = '<Author>'
subst = ' <Author>' + domain + '\\' + user_name + '</Author>'
line_index =0 #set line count to 0 before starting
file = io.open('a/b.xml', 'r', encoding='utf-16')
lines = file.readlines()
outFile = open('a/c.xml', 'w')
for line in lines[0:len(lines)]:
line_index =line_index +1
if line_index == len(lines):
#1. & 2. delete last line and adding another line in its place not writing it
outFile.writelines("Write extra line here" + '\n')
# 4. Close root tag:
outFile.writelines("</phonebook>") # as in:
#http://tizag.com/xmlTutorial/xmldocument.php
else:
#3. Substitue a line if it finds the following substring in a line:
pattern = '<Author>'
subst = ' <Author>' + domain + '\\' + user_name + '</Author>'
if pattern in line:
line = subst
print line
outFile.writelines(line)#just writing/copying all the lines from the original xml except for the last.