Replace specific XML attribute value

Question

I looked on the internet but I couldn't find a working answer to my question. I need to replace an XML file attribute value if it is size="10.439" to size="10.238". Basically, I need to change that number in the whole XML file. So the code is:

import lxml.etree as etree
import re
parser = etree.XMLParser(remove_blank_text=True)
tree = etree.parse('fe3.xml', parser)
re.sub(r'size="10.439"','size="10.238"', tree)

But it won't work, what do I have to do to make it work?

If it helps, the size attribute is in the tag text of the XML. Like this:

<pages>
<page>
<textbox>
<text size = "10.439"> hello
</text>
</textbox>
</page>
</pages>

You do not need any regex here. `re.sub(r'size="10.439"','size="10.238"', tree)` is the same as `tree.replace(r'size="10.439"','size="10.238"')`. Note you did not assign the value to a variable after replacing. — Wiktor Stribiżew, May 07 '20 at 13:46
I get AttributeError: 'lxml.etree._ElementTree' object has no attribute 'replace' — Anna, May 07 '20 at 13:48
So that was what you meant by "does not work". You can only use a regex with a string. You need to get the attributes you need with the XML parser and set the values with what you need, rather than using a regex against an XML structure. — Wiktor Stribiżew, May 07 '20 at 13:52
I'm new to XML, I don't know how to do it, since I have to change it under condition — Anna, May 07 '20 at 13:53
See [here](https://stackoverflow.com/questions/8171146/python-lxml-modify-attributes) for an example. — Wiktor Stribiżew, May 07 '20 at 13:55
@Anna - The [xpath tag info page](https://stackoverflow.com/tags/xpath/info) has some suggestions on XPath tutorials/online training. If you're working with XML, XPath is a must have skill in my opinion. — Daniel Haley, May 07 '20 at 16:04

score 1 · Answer 1 · answered May 07 '20 at 15:14

1

My dirty solution:

tree = etree.parse('fe3.xml', parser)
tree = etree.tostring(tree).replace(b'size="10.439"', b'size="10.238"')

answered May 07 '20 at 15:14

haja

88
3

score 0 · Answer 2 · answered May 13 '20 at 00:23

I'm here again :)

from simplified_scrapy import SimplifiedDoc,req,utils
html = '''
<pages>
<page>
<textbox>
<text size = "10.439"> hello
</text>
</textbox>
</page>
</pages>
'''
doc = SimplifiedDoc(html)
text = doc.select('text')
if text.size=='10.439':
  text.setAttr('size','10.238')
print (doc.html)

Result:

<pages>
<page>
<textbox>
<text size="10.238"> hello
</text>
</textbox>
</page>

Replace specific XML attribute value

2 Answers2