How to find, read and replace a value in XML file with Python

Question

This is my example XML file:

<CATALOG>
<CD>
<DATA key="title">Hide your heart</DATA>
<DATA key="artist">Bonnie Tyler</DATA>
<DATA key="country">UK</DATA>
<DATA key="company">CBS Records</DATA>
<DATA key="price">9.90</DATA>
<DATA key="year">1988</DATA>
<DATA key="times">1</DATA>
</CD>
</CATALOG>

I want to change the value in the the tag data with key "times" and add 1 to it every time I start the script from the terminal.

I tried first of all to read the element with:

import xml.etree.ElementTree
e = xml.etree.ElementTree.parse('test.xml').getroot()

for atype in e.findall('data'):
    times=(atype.get('times'))

But i'm already stuck because it doesn't work. If I try to print "times" I get no output from the terminal.

My Idea was to read it, with a function add to this value 1 and replace it with the total of the sum (2 in this case). And save the modified XML file.

It should be easy to do but I can't figure it out.

EDIT I had to read better the documentation, I tried with:

import xml.etree.ElementTree as ET
tree = ET.parse('test.xml')
root = tree.getroot()

times = root[0][7].text

newTimes = int(times) + 1

times = newTimes

tree.write('test.xml')

It read correctly the value, add 1 but gives an error if I try to write the file. What am I doing wrong?

EDIT 2
I found the solution, read below my own answer.

This is clearly explained in the ElementTree documentation. You're trying to read the attributes of a DATA element. IOW, you're trying to identify the DATA element which has an attribute key which has the value times. — Ken White
– Ken White, Commented Nov 22, 2017 at 16:30
You're right, my bad, I had to read better the documentation.. I edited my answer if you would like to help me. — Danny_DD
– Danny_DD, Commented Nov 22, 2017 at 16:54

Prune · Accepted Answer · 2017-11-22 16:34:02Z

0

Very simply:

>>> e.findall('CD')
[<Element 'CD' at 0x7fc0a22c1778>]
>>> e.findall('DATA')
[]

Wrong level of chacking ...

answered Nov 22, 2017 at 16:34

Prune

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Danny_DD · Accepted Answer · 2017-11-22 17:56:34Z

0

I found the solution, I only had to first read the value, turn it in an integer, add 1 and replace the value turning it again into a string:

import xml.etree.ElementTree as ET
tree = ET.parse('test.xml')
root = tree.getroot()

newTimes = int(root[0][7].text) + 1
root[1][6].text = str(newTimes)

tree.write('test.xml')

That's all.

answered Nov 22, 2017 at 17:56

Danny_DD

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