Day 53: Objects with class in Python
Do you know what class means ?
If you have class, it means you are a true Gentleman/Lady.
In python, it’s a little different
A class is a group of objects which share the same attributes.
A class, therefore serves as a blueprint for objects.
We say all the objects are of the same class.
It’s the basis of what we call OOP (Object-Oriented Programming)
In real life, what does that mean?
Let us take a Forex machine as an example.
A machine that converts your American Dollars to Mauritian Rupees.
Initializing class
class Forex:
""" Creates a new foreign exchange object """
def __init__(self, amount, currency):
# attributes defined for a transaction input
self.amount = amount
self.currency = currency
self.safe_balance = 100000
self.converted_funds = 0
Our class name is Forex. A class name should always start with a capital letter.
By using the init method, we create an instance of a class.
The init method contains various attributes such as the:
-
amount = amount of money given by the customer
-
currency = the end currency that the user requires.
-
safe_balance = the amount of money we currently have in the dispenser.
-
converted_funds = the funds that are awaiting conversion, initially set to 0.
First method
Inside our class, our first method would look just like a function.
But unlike a function, it is bound to the class.
This one just confirms what the customer typed on the screen.
class Forex:
""" Creates a new foreign exchange object """
def __init__(self, amount, currency):
# attributes defined for a transaction input
self.amount = amount
self.currency = currency
self.safe_balance = 100000
self.converted_funds = 0
def claimed_input(self):
return f"[LOG] {self.amount} claimed and requests output as {self.currency}"
Full code with more methods
class Forex:
""" Creates a new foreign exchange object """
def __init__(self, amount, currency):
# attributes defined for a transaction input
self.amount = amount
self.currency = currency
self.safe_balance = 100000
self.converted_funds = 0
def claimed_input(self):
return f"[LOG] {self.amount} claimed and requests output as {self.currency}"
def act_open_drawer(self):
return f"[ACT] Robot is now opening the money drawer.\n--> Please Insert the money in the drawer"
def count_money(self):
return f"[ACT] Robot is now counting money and confirms it has received {self.amount}"
def get_exc_rate(self):
self.dollartomu = 40
return f"[LOG] Got exchange rate of 1$ = {self.dollartomu}"
def convert_funds(self):
amt = self.amount
amount_flat = amt.replace('$', '')
self.converted_funds = int(self.dollartomu) * int(amount_flat)
return f"[LOG] Converted funds is {self.converted_funds}"
def check_safe_balance(self):
if self.converted_funds < self.safe_balance:
return f"--> Please take your {self.converted_funds}"
else:
return f"Sorry, we don't have enough funds\n--> Your money is now returned."
Creating a SMALL transaction
Once our class is complete, we’ll create a new forex transaction.
Starting with $100
# Create an instance from a class, here we have transact
transact = Forex('$1000', 'MUR')
print (transact.claimed_input())
print (transact.act_open_drawer())
print (transact.count_money())
print (transact.get_exc_rate())
print (transact.convert_funds())
print (transact.check_safe_balance())
Output
[LOG] $100 claimed and requests output as MUR
[ACT] Robot is now opening the money drawer.
--> Please Insert the money in the drawer
[ACT] Robot is now counting money and confirms it has received $100
[LOG] Got exchange rate of 1$ = 40
[LOG] Converted funds is 4000
--> Please take your 4000
Creating a MASSIVE transaction
Let’s go with $10000
# Create another instance of the class, transact2!
transact2 = Forex('$10000', 'MUR')
print (transact.claimed_input())
print (transact.act_open_drawer())
print (transact.count_money())
print (transact.get_exc_rate())
print (transact.convert_funds())
print (transact.check_safe_balance())
Output
[LOG] $10000 claimed and requests output as MUR
[ACT] Robot is now opening the money drawer.
--> Please Insert the money in the drawer
[ACT] Robot is now counting money and confirms it has received $10000
[LOG] Got exchange rate of 1$ = 40
[LOG] Converted funds is 400000
Sorry, we don't have enough funds
--> Your money is now returned.
