Merge or add content of file 2 to file 1 at a selected place in Python

Question

file 1:

<xmlsource>
    <sections>
        <section>
            <name>section 1</name>
            <path>path to section 1</path>
        </section>  
    </sections>
    <items>
        <item>
            <name>item 1</name>
            <path>path to item 1</path>
        </item>
        <item>
            <name>item 2</name>
            <path>path to item 2</path>
        </item>     
    </items>
    <forms>
        <form>
            <name>form 1</name>
            <path>path to form 1</path>
        </form> 
    </forms>
</xmlsource>

file 2:

<item>
    <name>item 3</name>
    <path>path to item 3</path>
</item>
<item>
    <name>item 4</name>
    <path>path to item 4</path>
</item>

How to merge/append file 2 into file 1 as follow (using Python):

<xmlsource>
    <sections>
        <section>
            <name>section 1</name>
            <path>path to section 1</path>
        </section>  
    </sections>
    <items>
        <item>
            <name>item 1</name>
            <path>path to item 1</path>
        </item>
        <item>
            <name>item 2</name>
            <path>path to item 2</path>
        </item> 
        <item>
            <name>item 3</name>
            <path>path to item 3</path>
        </item>
        <item>
            <name>item 4</name>
            <path>path to item 4</path>
        </item>     
    </items>
    <forms>
        <form>
            <name>form 1</name>
            <path>path to form 1</path>
        </form> 
    </forms>
</xmlsource>

a. The order of item 1 - item 4 are not important as long as they are in the same group

<items>
......
</items>

b. After merging/appending, the tabs in new file must match/be the same.

Thanks a bunch.

            ____________________________

I've saved file1 as sample1.xml, file2 as sample2.xml, and the below python code as combinexml.py, and saved all of them in C:\Users\BB\Desktop\CombineXML\ then run them using IDLE. Here what I got, please help

Traceback (most recent call last):
  File "C:\Users\BB\Desktop\CombineXML\combinexml.py", line 46, in <module>
    r = XMLCombiner(('sample1.xml', 'sample2.xml')).combine()
  File "C:\Users\BB\Desktop\CombineXML\combinexml.py", line 7, in __init__
    self.roots = [et.parse(f).getroot() for f in filenames]
  File "C:\Python27\lib\xml\etree\ElementTree.py", line 1182, in parse
    tree.parse(source, parser)
  File "C:\Python27\lib\xml\etree\ElementTree.py", line 656, in parse
    parser.feed(data)
  File "C:\Python27\lib\xml\etree\ElementTree.py", line 1642, in feed            self._raiseerror(v)
  File "C:\Python27\lib\xml\etree\ElementTree.py", line 1506, in _raiseerror
    raise err
ParseError: junk after document element: line 5, column 8

If this code works, what is the name and location of combined xml? Or either file1 or file2 will have the merged files and no new xml file created? Thank you.

You try something? Which Parser you used lxml ? Need wrapper also in second file. — Vivek Sable, Jul 13 '15 at 02:32
I'm a bit confused by your example data. Is `item 1` the same thing in both files, or are you renumbering the items to get `item 3`? The error you're showing has to do with trying to parse the second file as a single XML document, which it is not, since there are multiple top level elements (rather than a root element that contains all the rest). — Blckknght, Jul 14 '15 at 01:39
Just corrected item number in file2. I want to merge file2 into file1, do not know how and tried the code and got error. — user3833361, Jul 14 '15 at 01:55

score 0 · Answer 1 · edited May 23 '17 at 11:44

From the answer:

from xml.etree import ElementTree as et

class XMLCombiner(object):
    def __init__(self, filenames):
        assert len(filenames) > 0, 'No filenames!'
        # save all the roots, in order, to be processed later
        self.roots = [et.parse(f).getroot() for f in filenames]

    def combine(self):
        for r in self.roots[1:]:
            # combine each element with the first one, and update that
            self.combine_element(self.roots[0], r)
        # return the string representation
        return et.tostring(self.roots[0])

    def combine_element(self, one, other):
        """
        This function recursively updates either the text or the children
        of an element if another element is found in `one`, or adds it
        from `other` if not found.
        """
        # Create a mapping from tag name to element, as that's what we are fltering with
        mapping = {el.tag: el for el in one}
        for el in other:
            if len(el) == 0:
                # Not nested
                try:
                    # Update the text
                    mapping[el.tag].text = el.text
                except KeyError:
                    # An element with this name is not in the mapping
                    mapping[el.tag] = el
                    # Add it
                    one.append(el)
            else:
                try:
                    # Recursively process the element, and update it in the same way
                    self.combine_element(mapping[el.tag], el)
                except KeyError:
                    # Not in the mapping
                    mapping[el.tag] = el
                    # Just add it
                    one.append(el)

if __name__ == '__main__':
    r = XMLCombiner(('sample1.xml', 'sample2.xml')).combine()
    print '-'*20
    print r

Merge or add content of file 2 to file 1 at a selected place in Python

1 Answers1