CODEWITHSUNDEEP
python
Hector Hawkins
Hector Hawkins

Reputation: 23

Dice Roller in Python Not Random

I made a dice roller in python recently. However, the outputs seem to be fairly non-random (e.g. numbers coming up regularly twice in a row). Is this to do with my poor code or is the random.randint function not as random as it seems?

import random
print('Welcome to Dice Rolling simulator! \
Type "Roll" to start.')
def DiceRoll():    
    if input() == (str('Roll')):
    print(spam)
    print('Roll again?')
for i in range (50):
    spam = random.randint(1,6)
    DiceRoll()

Upvotes: 0

Views: 1127

Answers (2)

Reverse
Reverse

Reputation: 105

One way to verify the randomness of your function is to call it enough times, and verify the output distribution. The following code does so.

import random
def DiceRoll():
    return random.randint(1,6)

hist = []
for i in range(100000):
    hist.append(DiceRoll())

for j in range(1,7):
    print("Pr({}) = {}".format(j,hist.count(j)/len(hist)))

This yields :

Pr(1) = 0.16546
Pr(2) = 0.16777
Pr(3) = 0.16613
Pr(4) = 0.16534
Pr(5) = 0.1675
Pr(6) = 0.1678

Which seems to be perfectly random.

Upvotes: 3

Rushabh Mehta
Rushabh Mehta

Reputation: 1559

As @Arne noticed in the comments, dice rolls repeating is desired behavior in "random" rolls (in this case, pseudo-random, but I'm pretty sure it doesn't make a difference for your application).

However, if the repeats are really bothering you, it wouldn't be hard to prevent re-rolls, e.g. the following:

import random
print('Welcome to Dice Rolling simulator! \
Type "Roll" to start.')
spam = random.randint(1,6)
def DiceRoll(spam):    
    if input() == (str('Roll')):
    print(spam)
    print('Roll again?')
for i in range (50):
    DiceRoll(spam)
    spam2 = random.randint(1,5)
    spam = spam2//spam*(spam+1) + spam2%spam

Upvotes: 0

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