Have you ever wondered how spam bots create their spam messages?
This is probably how: They use Markov-Chains.
Given one word as input, a Markov Chain will put out another word. The output word is defined by a certain probability. It might be word A with probability of 20% or word B with probability of 80%. This word output is again used as input to get the next word, thus forming a chain of words.
This is my Glibberish-O-Mat that uses this principle. It takes as input a text file (you can use one from Project Gutenberg to get a reasonably long text:
http://www.gutenberg.org/ ), analyses the probabilities of the words following other words and then produces a text with the given amount of words using these probabilities.
Usage: glibberish.py <filename> <wordstogenerate>Example usage: python glibberish.py pg28203.txt 100Example output:
Python source (Python 2.7):import sys
import operator
import random
markov_chain = {}
#adds the specified word to the markov chain
def add_to_chain(lastword, word):
if not markov_chain.has_key(lastword):
markov_chain[lastword] = {}
if not markov_chain[lastword].has_key(word):
markov_chain[lastword][word] = 1
else:
markov_chain[lastword][word] += 1
#builds up the markov chain using the specified file
def build_chain_from(filename):
file = open(filename, 'r')
lastword = "first"
for word in words(file):
add_to_chain(lastword, word)
lastword = word
#iterates over words in a file
def words(file):
for line in file:
for word in line.split():
yield word
#returns a random word with the probability based on the given lastword
def get_rand_word(lastword):
chain = markov_chain[lastword]
total = sum(chain.itervalues())
randval = random.randint(1, total)
for key in chain:
randval -= chain[key]
if randval <= 0:
return key
return ""
#generates a text with the given amount of words
def generate_text(amount):
lastword = "first"
word = get_rand_word(lastword)
for i in range(0, amount):
word = word + " " + get_rand_word(lastword)
return word
def print_title():
print('''
_____ _ _ _ _ _ _
| __ \| |(_)| | | | (_) | |
| | \/| | _ | |__ | |__ ___ _ __ _ ___ | |__
| | __ | || || '_ \ | '_ \ / _ \| '__|| |/ __|| '_ \
| |_\ \| || || |_) || |_) || __/| | | |\__ \| | | |
\____/|_||_||_.__/ |_.__/ \___||_| |_||___/|_| |_|
_____ ___ ___ _
| _ | | \/ | | |
______ | | | | ______ | . . | __ _ | |_
|______|| | | ||______|| |\/| | / _` || __|
\ \_/ / | | | || (_| || |_
\___/ \_| |_/ \__,_| \__|
''')
def main():
print_title()
if len(sys.argv) != 3 or not sys.argv[2].isdigit():
print "usage: glibberish.py <filename> <wordstogenerate>"
return
filename = sys.argv[1]
amount = int(sys.argv[2])
build_chain_from(filename)
print generate_text(amount)
print
main()
