# Define a list named 'fruits' that contains three string elements: 'apple', 'banana', and 'cherry'.
fruits = ['apple', 'banana', 'cherry']

# Start a for loop that iterates over each element in the 'fruits' list.
# The variable 'fruit' will take on the value of each element in the list in each iteration.
for fruit in fruits:
    # Print the current value of 'fruit' to the console. On each iteration,
    # this will print 'apple', 'banana', and then 'cherry'.
    print(fruit)

# Output:
# apple
# banana
# cherry

# Initialize a variable 'count' to 0. This will be used to keep track of our loop iterations.
count = 0

# Start a while loop that will continue to execute as long as the value of 'count' is less than 5.
while count < 5:
    # Print the current value of 'count'. The f-string provides a readable format.
    print(f"Count is: {count}")
    
    # Increment 'count' by 1. This is crucial to eventually break out of the loop,
    # preventing an infinite loop scenario.
    count += 1

# Output:
# Count is: 0
# Count is: 1
# Count is: 2
# Count is: 3
# Count is: 4

# Loop through numbers from 0 to 9
for num in range(10):
    # Check if current number is equal to 5
    if num == 5:
        break  # If num is 5, exit the loop immediately
    
    # Check if the current number is even
    if num % 2 == 0:
        continue  # If num is even, skip the rest of the loop and move to the next iteration
    
    # If the number is odd and not 5, print it
    print(num)

# Output:
# 1
# 3

# This loop will iterate over a sequence of numbers generated by the range function.
# 'range(5)' generates a sequence of numbers from 0 to 4.
for num in range(5):
    # During each iteration, the current number in the sequence is printed.
    print(num)

# The 'else' block following the loop is executed only when the loop concludes naturally,
# meaning it doesn't encounter a 'break' statement.
else:
    # Since there are no 'break' statements in the loop, this message 
    # will be printed after the loop finishes iterating over all numbers.
    print("Loop completed naturally.")

# Output:
# 0
# 1
# 2
# 3
# 4
# Loop completed naturally.

# Outer loop: iterates 3 times with the variable i
for i in range(3):
    # Inner loop: iterates 2 times with the variable j each time the outer loop iterates
    for j in range(2):
        # Print the current values of i and j using an f-string for formatting
        print(f"i = {i}, j = {j}")

# Output
# i = 0, j = 0
# i = 0, j = 1
# i = 1, j = 0
# i = 1, j = 1
# i = 2, j = 0
# i = 2, j = 1

# Define a 2D list (matrix) with 3 rows and 3 columns
matrix = [
    [1, 2, 3],   # First row
    [4, 5, 6],   # Second row
    [7, 8, 9]    # Third row
]

# Iterate over each row in the matrix
for row in matrix:
    # Iterate over each element in the current row
    for element in row:
        # Print the element followed by a space, without moving to a new line
        print(element, end=' ')
    
    # After printing all elements in the row, move to the next line
    print()

# Output:
# 1 2 3
# 4 5 6
# 7 8 9

[expression for item in iterable if condition]

# List comprehension to generate a list of squared numbers from 0 to 9
# `x**2` means x raised to the power of 2 (x squared)
# `for x in range(10)` iterates through numbers 0 to 9
squares = [x**2 for x in range(10)]

# Output the list to the console
print(squares)  

# Expected output: [0, 1, 4, 9, 16, 25, 36, 49, 64, 81]

# Create a list comprehension to generate even squares
# List comprehensions provide a concise way to create lists

# Initialize an empty list to hold squares of even numbers
even_squares = [
    x**2                     # Iterate through numbers, square each number (x^2)
    for x in range(10)       # x takes values from 0 to 9 inclusive (range(10))
    if x % 2 == 0            # Include only if the number (x) is even (i.e., x % 2 == 0 is True)
]

# Print the resulting list of even squares
print(even_squares)

# Expected output: [0, 4, 16, 36, 64]

(expression for item in iterable if condition)

# This line creates a generator expression. A generator is like a list comprehension
# but it generates values one at a time and only when needed, which can be more memory efficient.
# Here, the generator will produce the squares of numbers from 0 to 9.
gen = (x**2 for x in range(10))

# This line starts a for loop that will iterate over each value generated by the generator 'gen'.
for value in gen:
    # Inside the loop, each value produced by the generator is printed.
    # The `end=' '` argument ensures that the printed values are separated by spaces instead of newlines.
    print(value, end=' ')

# Output:
# 0 1 4 9 16 25 36 49 64 81

# List of student scores
student_scores = [85, 90, 78, 92, 66, 54, 48, 37, 61, 88, 75, 99, 45, 77]

def calculate_statistics(scores):
    # Initialize variables to store statistics
    total_score = 0
    highest_score = scores[0]
    lowest_score = scores[0]
    number_of_students = len(scores)
    students_passed = 0

    # Loop through the scores to calculate the required statistics
    for score in scores:
        # Add to the total score
        total_score += score
        
        # Check for the highest score
        if score > highest_score:
            highest_score = score
            
        # Check for the lowest score
        if score < lowest_score:
            lowest_score = score
            
        # Count the number of students who passed
        if score >= 50:
            students_passed += 1
            
    # Calculate the average score
    average_score = total_score / number_of_students
    
    return average_score, highest_score, lowest_score, students_passed


def main():
    # Calculate statistics
    average_score, highest_score, lowest_score, students_passed = calculate_statistics(student_scores)
    
    # Print out the results
    print(f"Average Score: {average_score:.2f}")
    print(f"Highest Score: {highest_score}")
    print(f"Lowest Score: {lowest_score}")
    print(f"Number of Students Passed: {students_passed}")

if __name__ == "__main__":
    main()