如何用字符串替换lxml中的元素

Question

I'm trying to figure out in lxml and python how to replace an element with a string.

In my experimentation, I have the following code:

from lxml import etree as et

docstring = '<p>The value is permitted only when that includes <xref linkend=\"my linkend\" browsertext=\"something here\" filename=\"A_link.fm\"/>, otherwise the value is reserved.</p>'

topicroot = et.XML(docstring)
topicroot2 = et.ElementTree(topicroot) 
xref = topicroot2.xpath('//*/xref')
xref_attribute = xref[0].attrib['browsertext']

print href_attribute

The result is: 'something here'

This is the browser text attribute I'm looking for in this small sample. But what I can't seem to figure out is how to replace the entire element with the attribute text I've captured here.

(I do recognize that in my sample I could have multiple xrefs and will need to construct a loop to go through them properly.)

What's the best way to go about doing this?

And for those wondering, I'm having to do this because the link actually goes to a file that doesn't exist because of our different build systems.

Thanks in advance!

Answer 1

Try this (Python 3):

from lxml import etree as et

docstring = '<p>The value is permitted only when that includes <xref linkend=\"my linkend\" browsertext=\"something here\" filename=\"A_link.fm\"/>, otherwise the value is reserved.</p>'

# Get the root element.
topicroot = et.XML(docstring)
topicroot2 = et.ElementTree(topicroot)

# Get the text of the root element. This is a list of strings!
topicroot2_text = topicroot2.xpath("text()")

# Get the xref elment.
xref = topicroot2.xpath('//*/xref')[0]
xref_attribute = xref.attrib['browsertext']

# Save a reference to the p element, remove the xref from it.
parent = xref.getparent()
parent.remove(xref)

# Set the text of the p element by combining the list of string with the
# extracted attribute value.
new_text = [topicroot2_text[0], xref_attribute, topicroot2_text[1]]
parent.text = "".join(new_text)

print(et.tostring(topicroot2))

Output:

b'<p>The value is permitted only when that includes something here, otherwise the value is reserved.</p>'