CODEWITHSUNDEEP
python-2.7
Karneia
Karneia

Reputation: 23

Python - Rolled 2 6-side die 1000 times

This is for a programming class using python2. Instructions are to simulate rolling a pair of die 1000 times, store the results in a list and display the percentage of time each roll occurs.

Example of what output should be:

Here's my current code:

#!/usr/bin/python

import random

rolls = [0]*12

for v in range(1000):
d1 = random.randint(1,6)
d2 = random.randint(1,6)
rolls[d1 + d2 -1] += 1

print("Rolled %s %d times, or %.2f %" % (str(rolls)))

Right now I'm getting "TypeError: not enough arguments for format string".

I realize that I need to define a reference for %d and %.2f (and I realize that using %'s is going the way of .format, but this is how the professor has asked for it - hasn't taught how to use .format). I'm not sure how to reference the %d and the %.2f.

I know the %d needs to be a count of how many times a certain number was rolled, but am stuck at how to define and reference it. The %.2f needs to use the definition for the count/1000.

So, I think in my print line I need something like 

print("Rolled %s %d times, or %.2f %" % (str(rolls), count, count/1000))

Any insight/corrections would be appreciated.

Upvotes: 2

Views: 3539

Answers (3)

addi wei
addi wei

Reputation: 71

The first answer is not 100% correct because he/she added is returning or setting default to 1 and then adding another one which is incrementing total count. Total count will be over 1000 in that case. Here is the correct code:

for _ in range(1000):
    d1 = random.randint(1,6)
    d2 = random.randint(1,6)
    results[d1+d2] = results.setdefault(d1+d2, 0) + 1

for roll, count in results.iteritems():
    print('Rolled %d %d times, or %.2f %%' % (roll, count, count/1000))

Upvotes: 0

Ben
Ben

Reputation: 7124

This is covered in the Python Docs: http://docs.python.org/2/library/stdtypes.html#string-formatting

But for each % you need a value to substitute in:

for roll_value, roll_count in enumerate(rolls):
    print "Rolled %s %d times, or %.2f %%" %((roll_value+1), roll_count, (roll_count/1000.)*100)

*note the %% to print out the %sign, and the 1000. to return a type float

Upvotes: 1

Burhan Khalid
Burhan Khalid

Reputation: 174622

A dictionary would be another option, and it would look like this:

import random

results = {}

for _ in range(1000):
    d1 = random.randint(1,6)
    d2 = random.randint(1,6)
    results[d1+d2] = results.setdefault(d1+d2, 1) + 1

for roll, count in results.iteritems():
    print('Rolled %d %d times, or %.2f %%' % (roll, count, count/1000.))

setdefault will set a key to a value if it doesn't exist, otherwise it will return the value of the key.

Upvotes: 0

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