#function: renpy.random.randint()

[renpyhelpdesk]

Hey!! Thanks for your time. So I was wondering how I would write the code for something where I want the chances of success to be based on a percentage. I'm trying to implement lottery tickets, and I need it to have a 0.09% chance of success. And also, how would I make it so you get a different response for each outcome? Like if you failed to get one, I want your buddy to say "aw that's too bad, maybe next time!" And if not I want everyone to freak out, plus the earnings to be added. Thank you!!

I return from the void now that everyone is migrating back from the land of the South African Muskrat! Yours is a rather involved answer to see all of it below the cut

The answer to your question, at least the percentage part, is a matter of the randint() function in the Python library. In this case, you want something to happen only 1 in so many times. For example, 1 in 10 is a 10% chance. To simulate this in code, you can have the interpreter pick a random(note this isn’t true randomness, but it’s good enough for a video game we aren’t making a cyber security system!) number between 1 and 10. If it comes out to one number and one number only, then you pass the check. This makes it a 10% chance, just like if you rolled a 10 sided die. 

For your .09% chance(very rare!), it would be 1 in ~1,100 chance.(.090909...%). So if you have Python pick a number between 1 and 1,100 and check to see if it’s one specific number, then you’ll have your lottery win.

The easiest way to implement this in game is to record the results of the 1 in 1,100 chance inside a function wrapper so that you can call it multiple times and they can check lots of tickets.

init python:    def Lottery_Ticket():        ticket_num = renpy.random.randint(1, 1100)        return ticket_num

In order to use the randint() function from the random library, you just need to invoke it! It’s a part of Renpy’s library. So you’d type renpy.random.randint(1,1100) like above. :)

Once that is done in your game code itself you’ll put the logic for the winning number. Let’s say it’s 42, for meme reasons. 

You could write in your game file:

label check_ticket:    $ ticket = Lottery_Ticket()    if ticket == 42:        jump you_win    else:        jump you_lose

This simple logic sets the ticket equal to the result of the Lottery_Ticket function. It then checks if the number is exactly the winning number you chose. If so, it takes you to the winning section of your game code, if not, it falls through and says you lose.

Every time they buy a ticket, you can send them to this label, it will re-run the Lottery_Ticket function anew, picking a new random number, and see if they won.

Under your winning code, since you asked, this is where you’d put your characters reacting positively! Note the thing in brackets is the player character’s name as a variable being interpolated by the engine. If you let the player pick their own name, that’s how you’d get it into the script. If they have a set name, just type that instead. 

label you_win:    e “Oh my God! [PC_Name] you did it!    e “It’s like a dream come true!”    $ Inv.add(lottery_winnings)    $ renpy.notify(”You added“ + str(lottery_winnings) + “ to your wallet!”)

As you see, I’m using to functions. One that comes with Ren’Py calls in the notify screen context through the function. It needs to be a string inside which is why I’ve turned the int representing the lottery winnings into a string here.(This assumes you have a variable called “lottery_winnings” that has a specific integer value! Please initialize one before the start of your game!) (example: $ lottery_winnings = 10000)

The second is me assuming that you have an Inventory class instance with a method called “add” that can add money into a wallet variable. To make something like that:

init python:    class Inventory(python_object):        def__init__(self, wallet = 0):            self.wallet = wallet            self.pocket = []            def add(num):            self.wallet += num            return self.wallet

Then you just need an instance of it:$ Inv = Inventory() (I wrote it with defaults, so you don’t need to pass any arguments to the instance when you make it, though you are welcome to pass an INTEGER to it when you instantiate it so that your character starts with a certain amount of money. :D )

Then you can call the method on the variable to add the earnings to their wallet. :) 

There’s also an empty pockets list inside of the inventory you can use to store the string names of objects they also own. For something like that:

$ Inv.pocket.append(”apple”)

This will add a string called “apple” to the pocket list inside the inventory. Which you can use to check if they “own” an object by checking if it is in the list.

if ‘apple’ in Inv.pocket:    .......

But that’s more detail for another time. 

You need to put the class in an init python block before the game starts so that you can make an instance of it to manipulate later.

For not winning, just have the ‘you_lose’ label have the dialogue you wanted.

label you_lose:       e “Aw, that’s too bad. Maybe next time!”

And then continue on with the rest of the game.

I hope everything here is clear and this helps. I know this ask came in ages ago, but I still think answering it will help Ren’Py users in the now. Remember: If your code won’t compile, and you don’t what to do; who you gonna call? The Ren’Py Help Desk!