extract causation frame's Cause and Effect role from FrameNet annotated corpus

fn_extract_cause.py

from lxml import etree as ET
from itertools import chain
import sys

if len(sys.argv) > 1:
    f = open(sys.argv[1])
else:
    f = open('x.xml') # default xml file

# first, remove namespace
tree = ET.XML(f.read().replace(' xmlns=', ' xmlnamespace='))
f.close()
query = '''
//sentence[annotationSet[
             @frameName="Causation"]/layer[
                                        @name="FE" and
                                        label[@name="Cause"] and
                                        label[@name="Effect"]]]
'''
sens = tree.xpath(query)

check_frame = lambda x : x.get('frameName') == 'Causation'
for sen in sens:
    text = sen.find('text').text
    print "%-7s : %s" % ("TEXT", text)
    for i, a in enumerate(filter(check_frame, sen)):
        print "--- %d ---" % i
        causes = a.iterfind('layer[@name="FE"]/label[@name="Cause"]')
        effects = a.iterfind('layer[@name="FE"]/label[@name="Effect"]')
        for item in chain(causes, effects):
            s, e = item.get('start'), item.get('end')
            if s and e:
                print "%-7s : %s" % (item.get('name').upper(), 
                                     text[int(s):int(e)+1])
    print