wv.py

from bs4 import BeautifulSoup

s = '''STRING CON TODO EL HTML CONTENIDO EN LA ETIQUETA <div class="message-list"...> de http://web.whatsapp.com/'''

s = BeautifulSoup(s)
s = s.findAll('div', {'class':'bubble bubble-text'})

votes = {}
for l in s:
    try:
        autor = l.find('h3').text
        msgs = l.findAll('div', {'class':'message-text'})
        for msg in msgs:
            msg = msg.find('span').text
            msg = msg.upper()
            if 'VAGA SI' in msg:
                r = 1
            elif 'VAGA NO' in msg:
                r = 0
            elif 'VOTO EN BLANCO' in msg:
                r = -1
            else:
                r = None
            if r != None:
                if votes.has_key(autor):
                    print 'OVERRIDE_LAST_VOTE ->',
                print '[',r,'] ', autor, '->', msg
                votes[autor] = r 
    except Exception, E:
        pass

sis = 0.0
nos = 0.0
bla = 0.0
for k in votes.keys():
    if votes[k]==1:
        sis+=1
    elif votes[k]==0:
        nos+=1
    else:
        bla+=1

total = sis+nos+bla

print 'Participacion:', total
print '%SI:', sis/total*100
print '%NO:', nos/total*100
print '%BLACOS:', bla/total*100