Python - Random dice

I am a fairly new programmer, and I stumbled with a beginner practice project, a random dice number generator. The code works, but I would like to know if there is an efficient way compared to mine to write it.

#Random dice 
import random 

#returns a number (side of the dice)
def roll_dice():
  print (random.randint(1, 6)) 

print("""
Welcome to my python random dice program!
To start press enter!
Whenever you are over, type quit.
""")

flag = True
while flag:
   user_prompt = input(">")
   if user_prompt.lower() == "quit":
      flag = False
   else:
     print("Rolling dice...\nYour number is:") 
     roll_dice()

You can make it look nicer!

Instead of writing comments in front of your functions, do it with docstrings:

def roll_dice():
    """Print a number between 1 and 6 (side of the dice)"""
    print(random.randint(1, 6))

You can observe that I made a couple of changes to this:

• removed the extra space you had in your print() function

• added the docstring I mentioned above

• modified the content of docstring (your function doesn't return anything, it just prints a random number). A beginner programmer might get the wrong idea.

• used 4-spaces indentation instead of two.

• 2 new lines in front of your function

Now, let's try to make it even better!

You have two magic numbers, 1 and 6. Since you put the logic inside a function, let's make use of it and define those as arguments to our function:

def roll_dice(min_dice, max_dice):
    """Print a number between min_dice and max_dice (side of the dice)"""
    print(random.randint(min_dice, max_dice))

The above has the advantage of an easier customization of your program. More, you can abstract things even more, and give those arguments a default value:

def roll_dice(min_dice=1, max_dice=6):
    """Print a number between min_dice and max_dice (side of the dice)"""
    print(random.randint(min_dice, max_dice))

More, you can go a step further and make the function actually do something. Let's make it so that it returns a value. Just replace the print() function with return.

Okay, so far so good. I think we've managed to handle this part pretty well. Let's move on.

First, let's apply the changes we did in the first part, to this one too:

print("""
Welcome to my python random dice program!
To start press enter!
Whenever you are over, type quit.
""")

flag = True
while flag:
    user_prompt = input(">")
    if user_prompt.lower() == "quit":
        flag = False
    else:
        print("Rolling dice...\nYour number is:")
        roll_dice()

What I don't like about this, is the fact that you didn't wrap the logic inside a function. Let's do that first:

def play():
    print("""
    Welcome to my python random dice program!
    To start press enter!
    Whenever you are over, type quit.
    """)
    flag = True
    while flag:
        user_prompt = input("> ")
        if user_prompt.lower() == "quit":
            flag = False
        else:
            print("Rolling dice...\nYour number is:")
            roll_dice()

The changes that I'd like to make to this function are the following:

• remove the flag variable

-
move out the intro message in it

def play():
    while True:
        user_prompt = input("> ")
        if user_prompt.lower() == "quit":
            return False
        else:
            print("Rolling dice...\nYour number is: {}".format(roll_dice()))

Moving next, let's build our main() function:

def main():
    print("Welcome to my python random dice program!\n"
          "To start press ENTER!\n"
          "Whenever you are over, type quit.\n")
    play()

Last but not least, let's call our main function:

if __name__ == "__main__":
    main()

You can see I added an extra line: if __name__ == "__main__". By doing the main check, you can have that code only execute when you want to run the module as a program and not have it execute when someone just wants to import your module and call your functions themselves.

The full code:

import random

def roll_dice(min_dice=1, max_dice=6):
    """Print a number between min_dice and max_dice (side of the dice)"""
    return random.randint(min_dice, max_dice)

def play():
    """Return false if user enters 'quit'. Otherwise, print a random number"""
    while True:
        user_prompt = input("> ")
        if user_prompt.lower() == "quit":
            return False
        else:
            print("Rolling dice...\nYour number is: {}".format(roll_dice()))

def main():
    print("Welcome to my python random dice program!\n"
          "To start press ENTER!\n"
          "Whenever you are over, type quit.\n")
    play()

if __name__ == "__main__":
    main()

StackExchange Code Review Q#163134, answer score: 6