Data Structures

Introduction

• Now that you understand Python basics, let's learn how to organize and store multiple pieces of data efficiently.
• Data structures are containers that help you manage related information together.

Lists: Ordered Collections

• Lists store multiple items in a specific order. You can change, add, or remove items.
• “`python
• fruits = ['apple', 'banana', 'mango']
• print(fruits[0]) # Prints 'apple' (first item)
• fruits.append('orange') # Add item
• fruits.remove('banana') # Remove item
• print(len(fruits)) # Number of items
• “`

Dictionaries: Key-Value Pairs

• Dictionaries store data as pairs (like a real dictionary: word → meaning).
• “`python
• student = {
• 'name': 'Ali',
• 'age': 20,
• 'grade': 'A'
• }
• print(student['name']) # Prints 'Ali'
• student['city'] = 'Lahore' # Add new key
• “`
• Real Use Case: Store user information, product details, configuration settings.

Tuples: Unchangeable Lists

• Tuples are like lists but cannot be changed after creation.
• “`python
• coordinates = (23.5, 67.8)
• rgb_color = (255, 128, 0)
• “`
• Use tuples for data that should never change (e.g., coordinates, dates).

Real Example: Student Management

• “`python
• # List of dictionaries
• students = [
• {'name': 'Ahmed', 'marks': 85},
• {'name': 'Sara', 'marks': 92},
• {'name': 'Ali', 'marks': 78}
• ]
• # Find student with highest marks
• top_student = students[0]
• for student in students:
• if student['marks'] > top_student['marks']:
• top_student = student
• print(f"Top student: {top_student['name']} with {top_student['marks']} marks")
• “`