🐍 Python Basics Tutorial (with Output)

1. Data Types

Python has several built‑in data types. Some common ones:

• int – integer numbers, e.g. 5, -3
• float – decimal numbers, e.g. 3.14, -0.001
• str – strings (text), e.g. "hello", 'Python'
• bool – Boolean values: True, False
• list – ordered, mutable collection: [1, 2, 3]
• tuple – ordered, immutable collection: (1, 2, 3)
• dict – key‑value mapping: {'name':'Alice', 'age':30}
• set – unordered collection of unique items: {1,2,3}

Example:(save file name as datatype.py)

# Examples of data types
a = 10
b = 3.1415
c = "Hello, world!"
d = True
e = [1, 2, 3, 4]
f = (5, 6, 7)
g = {'name': 'Bob', 'age': 25}
h = {1, 2, 2, 3, 3, 3}

print(type(a), type(b), type(c), type(d))
print(e, f, g, h)

2. Variables

Variables are names that refer to values. Python is dynamically typed, so no need to declare types.

Example:(save filename as variables.py)

x = 5
y = "Python"
z = 3.5

print("x is", x)
print("y is", y)
print("z * x =", z * x)

x = 20
print("x is now", x)

3. Conditional Statements (if / elif / else)

Used to execute different code depending on conditions.

Example:(save filename as if-else.py)

num = 0

if num > 0:
    print("Positive")
elif num == 0:
    print("Zero")
else:
    print("Negative")

age = 25
if age < 13:
    print("Child")
elif 13 <= age < 20:
    print("Teenager")
elif 20 <= age < 65:
    print("Adult")
else:
    print("Senior")

4. Functions

Functions help organize reusable blocks of code.

Example:(save filename as function-example.py)

def greet(name):
    return f"Hello, {name}!"

def add(a, b):
    return a + b

msg = greet("Alice")
print(msg)

s = add(5, 7)
print("Sum is", s)

def power(base, exponent=2):
    return base ** exponent

print(power(4))
print(power(4, 3))

5. Classes and Object-Oriented Programming

Classes define blueprints; objects are instances of them.

Example:(save filename as class-example.py )

class Person:
    def __init__(self, name, age):
        self.name = name
        self.age = age

    def greet(self):
        print(f"Hi, I'm {self.name}, and I'm {self.age} years old.")

    def have_birthday(self):
        self.age += 1
        print(f"Happy birthday! I’m now {self.age}.")

p = Person("Charlie", 30)
p.greet()
p.have_birthday()
p.have_birthday()

6. Putting It All Together

Combining variables, conditionals, functions, and classes.

class BankAccount:
    def __init__(self, owner, balance=0):
        self.owner = owner
        self.balance = balance

    def deposit(self, amount):
        if amount > 0:
            self.balance += amount
            print(f"Deposited {amount}. New balance: {self.balance}")
        else:
            print("Deposit must be positive.")

    def withdraw(self, amount):
        if amount <= 0:
            print("Withdrawal amount must be positive.")
        elif amount > self.balance:
            print("Insufficient funds.")
        else:
            self.balance -= amount
            print(f"Withdrew {amount}. New balance: {self.balance}")

acct = BankAccount("Dana", 100)
acct.deposit(50)
acct.withdraw(30)
acct.withdraw(150)