双掷骰子

Question

My code currently rolls 2 dices 1,000 times and the output is how many times each number was rolled. However, I need to improve the code so that the output also includes every time a double is rolled. An example of what I need the output to be similar to is:

Snake Eyes were rolled 5 times

Double 2's were rolled 8 times

Double 3's were rolled 17 times 

And so on up til 6...

This is my current code which is working perfectly:

import random

test_data = [0] * 12
n = 1000
for i in range(n):
    result = random.randint(1, 6) + random.randint(1, 6)
    test_data[result - 1] += 1

for i, x in enumerate(test_data, 1):
    print ("Number of ", i, "'s: ", x)

The output is:

Number of  1 's:  0
Number of  2 's:  28
Number of  3 's:  56
Number of  4 's:  82
Number of  5 's:  107
Number of  6 's:  130
Number of  7 's:  172
Number of  8 's:  133
Number of  9 's:  115
Number of  10 's:  93
Number of  11 's:  56
Number of  12 's:  28

How can I improve my code so that "doubles" also appear?

Answer 1

split the line

 result = random.randint(1, 6) + random.randint(1, 6)

into

roll1 = random.randint(1, 6)
roll2 = random.randint(1, 6)

now you can test for doubles with:

if roll1 == roll2:
   #log double

Answer 2

You can create another list of 6 values for the doubles and slightly change the rest of your code:

import random

doubles = [0] * 6
test_data = [0] * 12
n = 1000

for i in range(n):
    a,b = random.randint(1, 6) , random.randint(1, 6) # create 2 distinct ones
    result = a+b                                      # and the sum
    test_data[result - 1] += 1
    if a == b:                                        # if a==b count up
        doubles[a-1] += 1


for i, x in enumerate(test_data, 1):
     if i > 1: # no sum of 1 possible
         print ("Number of {:>2}'s: {:>6}".format(i,x))

# output for doubles:
for i,x in enumerate(doubles,1):
    # python ternary operator, see link below
    print( ("Snake eyes were rolled {cnt} times" if i == 1 
            else "Double {}'s were rolled {cnt} times").format(i,cnt=x))

Output:

Number of  2's:     28
Number of  3's:     64
Number of  4's:     72
Number of  5's:    120
Number of  6's:    139
Number of  7's:    139
Number of  8's:    137
Number of  9's:    114
Number of 10's:     93
Number of 11's:     58
Number of 12's:     36
Snake eyes were rolled 28 times
Double 2's were rolled 28 times
Double 3's were rolled 25 times
Double 4's were rolled 23 times
Double 5's were rolled 28 times
Double 6's were rolled 36 times

Readup:

• string formatting mini language here to align output and format numbers into text
• python ternary operator SO-Question explaining that

Answer 3

I would use a Counter to store these kinds of dice counts, as it keeps the code nice and clean:

from collections import defaultdict, Counter
import random

dice_combined = Counter()
dice_individual = defaultdict(Counter)

for i in range(1000):
  a = random.randint(1, 6)
  b = random.randint(1, 6)
  dice_combined[a+b] += 1
  dice_individual[a][b] += 1

# print report:
for i in dice_combined:
  print(i, 'was rolled', dice_combined[i], 'times')

for i in range(1, 6, 1):
  print('double', i, 'was rolled', dice_individual[i][i], 'times')

Sample Report :

2 was rolled 25 times
3 was rolled 49 times
4 was rolled 77 times
5 was rolled 99 times
6 was rolled 150 times
7 was rolled 169 times
8 was rolled 140 times
9 was rolled 100 times
10 was rolled 101 times
11 was rolled 67 times
12 was rolled 23 times
double 1 was rolled 25 times
double 2 was rolled 29 times
double 3 was rolled 21 times
double 4 was rolled 23 times
double 5 was rolled 28 times