Python Data Structures

Data Structures in Python

Lists

• Ordered collection of items that can be of any data type, including strings, integers, floats, and other lists
• Can be indexed and sliced
• Can be modified (mutable)
• Example: my_list = [1, 2, 3, 4, 5]

Tuples

• Ordered, immutable collection of items
• Cannot be modified after creation
• Example: my_tuple = (1, 2, 3, 4, 5)

Dictionaries

• Unordered collection of key-value pairs
• Keys must be unique and immutable (strings, integers, etc.)
• Values can be of any data type
• Example: my_dict = {'name': 'John', 'age': 30}

Sets

• Unordered collection of unique items
• Items must be immutable (strings, integers, etc.)
• No duplicate items allowed
• Example: my_set = {1, 2, 3, 4, 5}

Arrays

• Not a built-in data structure in Python, but can be achieved using the array module
• One-dimensional, homogeneous, and mutable
• Example: from array import array; my_array = array('i', [1, 2, 3, 4, 5])

Other Data Structures

• Stack: Last-In-First-Out (LIFO) data structure, can be implemented using lists
• Queue: First-In-First-Out (FIFO) data structure, can be implemented using lists
• Heap: Special type of tree-based data structure, can be implemented using the heapq module
• Graph: Non-linear data structure composed of nodes and edges, can be implemented using dictionaries and lists

Data Structures in Python

Lists

• A collection of items that can be of any data type, including strings, integers, floats, and other lists
• Items in a list can be accessed and manipulated using indexing and slicing
• Lists are mutable, meaning they can be modified after creation

Tuples

• An ordered collection of items that cannot be modified after creation
• Tuples are immutable, meaning they cannot be changed once created
• Example: my_tuple = (1, 2, 3, 4, 5)

Dictionaries

• A collection of key-value pairs where keys are unique and immutable
• Keys can be strings, integers, or other immutable data types
• Values can be of any data type
• Example: my_dict = {'name': 'John', 'age': 30}

Sets

• A collection of unique items that are unordered
• Items in a set must be immutable
• Sets do not allow duplicate items
• Example: my_set = {1, 2, 3, 4, 5}

Arrays

• Not a built-in data structure in Python, but can be achieved using the array module
• Arrays are one-dimensional, homogeneous, and mutable
• Example: from array import array; my_array = array('i', [1, 2, 3, 4, 5])

Other Data Structures

Stacks

• A Last-In-First-Out (LIFO) data structure
• Can be implemented using lists
• Example: pushing and popping items from a list to mimic a stack

Queues

• A First-In-First-Out (FIFO) data structure
• Can be implemented using lists
• Example: using a list to implement a queue with enqueue and dequeue operations

Heaps

• A special type of tree-based data structure
• Can be implemented using the heapq module
• Example: using heapq to create a heap and perform heap operations

Graphs

• A non-linear data structure composed of nodes and edges
• Can be implemented using dictionaries and lists
• Example: representing a graph using an adjacency list or adjacency matrix

This quiz covers the basics of lists, tuples, and dictionaries in Python. Learn about the characteristics and uses of each data structure.