custom sorting xml

sort_xml.py

# -*- coding: utf-8 -*-
"""
Created on Tue May 24 06:12:11 2016

@author: sh.otsuka
"""

# experiment based on http://stackoverflow.com/a/8387132/1635993

from lxml import etree

data = """<X>
    <X03>3</X03>
    <X02>2</X02>
    <A>
        <A02>Y</A02>
        <A01>X</A01>
        <A03>Z</A03>
        <K>
          <J1>3</J1>
          <J3>5</J3>
          <J2>4</J2>
        </K>
        <K>
          <J3>1</J3>
          <J1>2</J1>
          <J2>3</J2>
        </K>
        <R id="3">1</R>
        <R id="1">2</R>
        <R id="2">3</R>
    </A>
    <X01>1</X01>
    <B>
        <B01>Z</B01>
        <B02>X</B02>
        <B03>C</B03>
    </B>
</X>"""

doc = etree.XML(data,etree.XMLParser(remove_blank_text=True))

#%% sort whole node
def parentsort(apath,keyformula):
    elements = doc.xpath(apath)
    for element in elements:
        element[:] = sorted(element,key=keyformula)

#%% partial sort
def siblingsort(parentpath,childTagFormula,keyformula):
    parents = doc.xpath(parentpath)
    for parent in parents:
        target_index = [i for i,child in enumerate(parent) if childTagFormula(child)]
        s,f  = min(target_index), max(target_index)+1
        parent[s:f] = sorted(parent[s:f],key=keyformula)
     
#%% sort A0N
parpath = '//A'
ct1 = lambda x: x.tag[0] == 'A'
k1 = lambda x: x.tag
siblingsort(parpath,ct1,k1)

#%% sort K
kpath = '//A/K'
k2 = lambda x: x.tag
parentsort(kpath,k2)

#%% sort R
ct2 = lambda x: x.tag == 'R'
k3 = lambda x: x.attrib['id']
siblingsort(parpath, ct2,k3)

#%% sort X0N
parentsort('//X',lambda x: x.tag) #somehow not necessary
ct3 = lambda x: x.tag[0] == 'X'
k4 = lambda x: x.tag
siblingsort('//X', ct3, k4)
#%% pretty print xml
print etree.tostring(doc,pretty_print=True)