Merge child nodes with the similar parent node, xml, python

Question

I have the following xml file:

<root>
    <article_date>09/09/2013
    <article_time>1
        <article_name>aaa1</article_name>
        <article_link>1aaaaaaa</article_link>
    </article_time>
    <article_time>0
        <article_name>aaa2</article_name>
        <article_link>2aaaaaaa</article_link>
    </article_time>
    <article_time>1
        <article_name>aaa3</article_name>
        <article_link>3aaaaaaa</article_link>
    </article_time>
    <article_time>0
        <article_name>aaa4</article_name>
        <article_link>4aaaaaaa</article_link>
    </article_time>
    <article_time>1
        <article_name>aaa5</article_name>
        <article_link>5aaaaaaa</article_link>
    </article_time>
    </article_date>
</root>

I would like to transform it to the following file:

<root>
    <article_date>09/09/2013
    <article_time>1
        <article_name>aaa1+aaa3+aaa5</article_name>
        <article_link>1aaaaaaa+3aaaaaaa+5aaaaaaa</article_link>
    </article_time>
    <article_time>0
        <article_name>aaa2+aaa4</article_name>
        <article_link>2aaaaaaa+4aaaaaaa</article_link>
    </article_time>
</root>

How can I do it in python?

My approach to do this task is the following: 1) loop through tags 2) form dictionary key- either 0 or 1, value - 3) for each element in this dictionary find all child nodes: and and append them

Since that, I wrote the following code to implement this (ps I am currently struggling with adding elements to the dictionary, but I will overcome this issue):

def parse():
list_of_inique_timestamps=[]
text_to_merge=""
tree=et.parse("~/Documents/test1.xml")
root=tree.getroot()
for children in root:
    print children.tag, children.text
    for child in children:
        print (child.tag,int(child.text))
        if not child.text in list_of_inique_timestamps:
            list_of_inique_timestamps.append(child.text)
print list_of_inique_timestamps

Answer 1

Here's the solution using xml.etree.ElementTree from python standard library.

The idea is to gather items into defaultdict(list) per article_time text value:

from collections import defaultdict
import xml.etree.ElementTree as ET

data = """<root>
    <article_date>09/09/2013
    <article_time>1
        <article_name>aaa1</article_name>
        <article_link>1aaaaaaa</article_link>
    </article_time>
    <article_time>0
        <article_name>aaa2</article_name>
        <article_link>2aaaaaaa</article_link>
    </article_time>
    <article_time>1
        <article_name>aaa3</article_name>
        <article_link>3aaaaaaa</article_link>
    </article_time>
    <article_time>0
        <article_name>aaa4</article_name>
        <article_link>4aaaaaaa</article_link>
    </article_time>
    <article_time>1
        <article_name>aaa5</article_name>
        <article_link>5aaaaaaa</article_link>
    </article_time>
    </article_date>
</root>
"""

tree = ET.fromstring(data)

root = ET.Element('root')
article_date = ET.SubElement(root, 'article_date')
article_date.text = tree.find('.//article_date').text

data = defaultdict(list)
for article_time in tree.findall('.//article_time'):
    text = article_time.text.strip()
    name = article_time.find('./article_name').text
    link = article_time.find('./article_link').text
    data[text].append((name, link))

for time_value, items in data.iteritems():
    article_time = ET.SubElement(article_date, 'article_time')
    article_name = ET.SubElement(article_time, 'article_name')
    article_link = ET.SubElement(article_time, 'article_name')

    article_time.text = time_value
    article_name.text = '+'.join(name for (name, _) in items)
    article_link.text = '+'.join(link for (_, link) in items)

print ET.tostring(root)

prints (prettified):

<root>
    <article_date>09/09/2013
        <article_time>1
            <article_name>aaa1+aaa3+aaa5</article_name>
            <article_name>1aaaaaaa+3aaaaaaa+5aaaaaaa</article_name>
        </article_time>
        <article_time>0
            <article_name>aaa2+aaa4</article_name>
            <article_name>2aaaaaaa+4aaaaaaa</article_name>
        </article_time>
    </article_date>
</root>

See, the result is exactly what you were aiming to.