Retrieve attribute names and values with Python / lxml and XPath

Question

I am using XPath with Python lxml (Python 2). I run through two passes on the data, one to select the records of interest, and one to extract values from the data. Here is a

Answer 1

I was wrong in my assertion that I was not going to use Python. I found that the lxml/etree implementation is easily extended to that I can use the XPath DSL with modifications.

I registered the function "dictify". I changed the XPath expression to :

dictify('@id|@height|@weight|weight|height')

The new code is:

from lxml import etree

xml = """

    
    150
    

"""

def dictify(context, names):
    node = context.context_node
    rv = []
    rv.append('__dictify_start_marker__')
    names = names.split('|')
    for n in names:
        if n.startswith('@'):
            val =  node.attrib.get(n[1:])
            if val != None:
                rv.append(n)
                rv.append(val)
        else:
            children = node.findall(n)
            for child_node in children:
                rv.append(n)
                rv.append(child_node.text)
    rv.append('__dictify_end_marker__')
    return rv

etree_functions = etree.FunctionNamespace(None)
etree_functions['dictify'] = dictify


parsed = etree.fromstring(xml)
nodes = parsed.xpath('/records/row')
for node in nodes:
    print node.xpath("dictify('@id|@height|@weight|weight|height')")

This produces the following output:

['__dictify_start_marker__', '@id', '1', '@height', '160', '@weight', '80', '__dictify_end_marker__']
['__dictify_start_marker__', '@id', '2', '@weight', '70', 'height', '150', '__dictify_end_marker__']
['__dictify_start_marker__', '@id', '3', '@height', '140', '__dictify_end_marker__']