Programming Lecture Notes

Basic Concepts

Data Types and Variables

• Integer: Whole numbers without a decimal. Example: a = 10, b = 20. Operations: +, -, *, /.
• String: Text enclosed in double quotes. Example: name = "EMC", age = "Porter".*

Input and Output

• Get input from users using input(). Example: name = input(), age = input().
• Print statements to output data. Example: print("My name is", name), print("My age is", age).

Conditional Statements

If-Else Statements

• Evaluates expressions and executes code blocks based on the truth value.
• Example: if a > 10: print("Greater than 10") else: print("10 or less")
• Nested If-Else for complex conditions.

Boolean Values

• Represented by True and False.
• Used in conditional expressions.

Logical Operators

• and, or, not: To combine multiple conditions.
• Example: if a > 10 and b < 20: print("Condition met")

Loops

For Loop

• Iterate over a sequence (e.g., list, range).
• Example: for i in range(5): print(i)
• Can be nested and combined with If-Else conditions.

While Loop

• Repeats as long as a condition is True.
• Example: i = 0 while i < 5: print(i) i += 1

Functions

Defining Functions

• Use def keyword to define a function.
• Example: def add(a, b): return a + b
• Function can call other functions and take parameters.

Return Statement

• Returns a value from a function.
• Example: return a + b

Input to Function

• Functions can take user input and process it.
• Example: def print_name(name): print("My name is", name)

Collections

Lists

• Ordered and changeable collection. Allow duplicate members.
• Example: a = [1, 2, 3, 4]
• Methods: append(), insert(), remove(), etc.

Set

• Unordered collection. No duplicate members.
• Example: a = {1, 2, 3}
• Methods: add(), remove(), etc.

Dictionary

• Collection of key-value pairs. Ordered since Python 3.7.
• Example: a = {"name": "EMC", "age": 25}
• Methods: items(), keys(), values()

Classes and Objects

Defining Classes

• Use class keyword.
• Example: class MyClass: x = 5

Object Instantiation

• Creating an instance of a class.
• Example: p1 = MyClass()

Methods

• Functions that belong to an object.
• Example: class MyClass: def __init__(self, name): self.name = name def greet(self): print("Hello,", self.name)

Inheritance

Single Inheritance

• One class inherits from another class.
• Example: class Parent: def display(self): print("Parent class") class Child(Parent): pass

Multiple Inheritance

• A class can be derived from more than one base class.
• Example: class A: pass class B: pass class C(A, B): pass

Overriding Methods

• A derived class can override methods of the base class.
• Example: class Parent: def show(self): print("Parent method") class Child(Parent): def show(self): print("Child method")

Error Handling

Exceptions

• Errors that occur during execution are called exceptions.
• Try-Except block to handle exceptions.
• Example: try: a = int(input("Enter a number: ")) b = int(input("Enter another number: ")) print(a / b) except ZeroDivisionError: print("Cannot divide by zero") except ValueError: print("Invalid input")

Logical Errors

• Bugs in the program that produce incorrect results.
• Not caught during compilation but cause problems during execution.