predict_next.py

import re
from operator import itemgetter
from collections import Counter

def clean_data(txt):
    txt = txt.lower()
    txt = txt.replace('mr.','mr').replace('mrs.','mrs').replace('ms.','ms')
    sentences = re.findall(r"[^!\.\?]+[!\.\?]",txt.lower())
    sentences = [s.replace('\n',' ').replace('\r',' ') for s in sentences] 
    sentences = [re.sub(r'[^a-z ]','',x) for x in sentences]
    return sentences

def build_db(rows):
    db = {} 
    for r in rows:
        words = r.split()
        lw = len(words) - 1
        for i,w in enumerate(words):
            if w not in db:
                db[w] = {}
            if i == lw: break
            nxt = words[i+1]
            if nxt not in db[w]:
                db[w][nxt] = 1
            else:
                db[w][nxt] += 1
    return db

if __name__=="__main__":
    rows = clean_data(open("test.txt").read())
    db = build_db(rows)

    while True:
        print "Word:"    
        word = raw_input().lower()
        if word not in db: print "(word not found)"
        c = Counter(db[word])
        print ' '.join([i[0] for i in c.most_common()[:3]])

            

foolish little hack to probabilistically predict the next word based upon what word you put in. Just came as a result of a conversation at pythonSD saturday meetup.