lxml.etree insert elements into element.text

Question

I have strings that have empty xml elements in them, like this:

>>> s = """fizz buzz <pb n="44"/> bananas"""

These strings have been assigned to xml elements using the etree.SubElement method:

>>> from lxml import etree as et
>>> root = et.Element('root')
>>> txt = et.SubElement(root, 'text')
>>> txt.text = s
>>> et.dump(root)
<root>
  <text>fizz buzz &lt;pb n="44"/&gt; bananas</text>
</root>

Fiddling about with re.split() and etree's text and tail I can insert a subelement <pb n="44"/> where I want it in txt.text; however, sometimes I've got multiple occurrences of the <pb/> element in the string, which complicates matters:

>>> s1 = """foo bar <pb n="42"/> parrots like <pb n="43"/> eggs and spam"""

Is there a straightforward way to insert such elements where they belong in an existing element's text without fiddling around too much with text and tail?

Answer 1

You could make your input string a well-formed XML document (with text as the root element) and parse that into an Element object using fromstring(). Then append it to the parent.

from lxml import etree as et

s1 = """foo bar <pb n="42"/> parrots like <pb n="43"/> eggs and spam"""
s2 = "<text>{0}</text>".format(s1)

text = et.fromstring(s2)
root = et.Element('root')
root.append(text)

et.dump(root)

Output:

<root>
 <text>foo bar <pb n="42"/> parrots like <pb n="43"/> eggs and spam</text>
</root>