We start section 4 with a very short introduction to randomization. Chapter 7 of BPB discuss the use of randomization to obtain mutations in DNA and protein sequences. The example given in the book is at the same time simple and interesting, as it creates a paragraph from random selections of nouns, adjectives, verbs and other grammar elements. Here we are going to to create a very (stress on very) simple dice game, where each time you run the script it will throw two dices for you and two dices for the computer. It then prints the sum of the dices and tells who won the match. Randomization is an important feature of computer languages. There are different researchers involved in the creation of the best approaches to generate random number in computers. Random number are important in the simulation of different natural processes, such as genetic mutation, gene drift, epidemiology, weather forecast, etc. The better the generator, the better the simulation. Python has a random module included, with a myriad of functions that can perform different randomizations. In this post we will see the integer randomization, and in later entries we will see some other powerful functions. Our script is quite simple, and the only new aspect for us here is the random module and the randint function.

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#!/usr/bin/env python 
import random

dice1 = random.randint(1,6)
dice2 = random.randint(1,6)
computerdice1 = random.randint(1,6)
computerdice2 = random.randint(1,6)
mine = dice1 + dice2

his = computerdice1 + computerdice2

print 'mine = ' + str(mine) + ' vs. computer = ' + str(his)

if mine > his:
    print "I won"
elif mine < his:
    print "Computer won"
else:
    print "Tie. Try again"

random.randint is a function that generates an integer random number between a range specified by the number between parentheses. In the above case, we are using a dice of 6 values. So, for every call of random.randint(1,6) a random number between 1 and 6 will be generated. We store this number in a variable, sum the user’s dices and the computer’s and check with a if clause to see the winner. A good exercise would be to make this script interactive, allowing multiple matches. Next we will see another random module function and then we will generate mutations on DNA sequences.