Python Basics: Data Structures and Control Flow

Study Notes

Data Structures

Data structures are organized ways to store and manage data. Examples include lists, tuples, dictionaries, and arrays.

Algorithms

Algorithms are step-by-step instructions used to solve problems efficiently.

Divide-and-Conquer

Divide-and-conquer is a problem-solving approach that involves recursively dividing a problem into smaller subproblems, solving them, and then combining the results.

Python Basics

Arithmetic Operators

+: Addition
-: Subtraction
*: Multiplication
/: Division

Control Flow

if: Conditional execution
for: Iterate over sequences
while: Repeat code while a condition is true
break: Exit a loop early
continue: Skip current iteration
pass: Placeholder for no action

Lists/Tuples

Lists: Mutable (can be changed) Example: my_list = [1, 2, 3]
Tuples: Immutable (cannot be changed) Example: my_tuple = (1, 2, 3)
Use len() to determine the length of a list or tuple

Dictionaries

Access elements using keys: Example my_dict["key"]

NumPy Essentials

Creating Arrays

np.array([1, 2, 3]) - Basic array
np.zeros((2, 3)) - Array filled with zeros.
np.random.rand(3, 3) - Array with random values

Accessing Elements

Single element: my_array[0]
2D element: my_array[0, 1]

Useful NumPy Methods

shape: Get array dimensions
reshape(): Change array shape (e.g., reshape(2, 3))
transpose: Swap rows and columns
sum(): Calculate the sum of elements (np.sum(my_array))
mean(): Calculate the average (np.mean(my_array))
std(): Calculate the standard deviation (np.std(my_array))

Stack and Queue Basics

Stack (LIFO)

push: Add data to the stack using stack.append(data)
pop: Remove data from the stack using stack.pop()
peek: View the top element using stack[-1]

Queue (FIFO)

enqueue: Add data to the queue using queue.append(data)
dequeue: Remove data from the queue using queue.pop(0)
front: Access the front element using queue[0]

Algorithms and Their Purposes

Depth First Search (DFS): Recursive search through graphs/trees
Breadth First Search (BFS): Level-by-level search through graphs/trees
Binary Search: Efficient search in a sorted array.
Bubble Sort: Sorting using repeated swaps.
Divide and Conquer: Solve problems by breaking them into smaller, more manageable subproblems.

Sample Code Outputs

Basic Math: Example of basic arithmetic calculation (output: 15).
NumPy Example: Example of creating and printing a NumPy array (output: array([1, 2, 3])).
Control Flow: Example of a for loop (output: 0, 1, 2, 3, 4).

Description

This quiz covers essential concepts in Python, focusing on data structures like lists and tuples, as well as control flow mechanisms such as loops and conditional statements. Test your understanding of fundamental programming principles and improve your coding skills.