find xml element based on its attribute and change its value

Question

I am using python xmlElementTree and want to assign or modify a xml element value based on its attribute. Can somebody give me an idea how to do this?

For example: Here

Answer 1

I'm not familiar with xmlElementTree, but if you're using something capable of xpath expressions you can locate a node by attribute value using an expression like this:

//number[@topic="sys/phoneNumber/1"]

So, using the etree module:

>>> import lxml.etree as etree
>>> doc = etree.parse('foo.xml')
>>> nodes = doc.xpath('//number[@topic="sys/phoneNumber/1"]')
>>> nodes
[]
>>> etree.tostring(nodes[0])
'\n    '