Why is this function undefined in this case

Python
1

Why does the usage of the withdraw function (in the if statement in the transfer function) make an error saying the function is undefined?

class Category:

    def __init__(self, name):
        self.ledger = []
        self.cat_name = name
        self.balance = 0
    
    def deposit(self, amount, description=""):
        self.balance += amount
        self.ledger.append({"amount": amount, "description": description})

    def withdraw(self, amount, description=""):
        if self.balance - amount >= 0:
            self.balance -= amount
            self.ledger.append({"amount": -1 * amount, "description": description})
            return True
        return False
    
    def get_balance(self):
        return self.balance
    
    def transfer(self, newcat, ammount):
        if(withdraw(amount, "Transfer to " + newcat.cat_name)):
2

All of these functions are defined as methods on instances of the object itself, much like the internal variables.

3

sorry I am not sure I understand what you mean

4

The balance variable is defined on the object itself. So in the withdraw method.

5

so how can I correct the error I am getting

6

Do you know how to call a method on an object in Python? For example, how you call .sort on a list in Python?

1 Like
7

ohh I understand now. I use self as the instance of the class and call the withdraw method on that.
like self.withdraw(amount, "Transfer")

1 Like
8

Bingo. Inside of the definition of the class, that’s how you call methods for the object.

9

This topic was automatically closed 182 days after the last reply. New replies are no longer allowed.