Loops allow you to execute a block of code multiple times. Python provides two types of loops:

Both loops are used to perform repetitive tasks but have different use cases and syntax.

The while loop executes a block of code as long as the given condition is True. It is primarily used when the number of iterations is not known beforehand.

while condition:
    # Code to execute repeatedly as long as the condition is True

count = 0
while count < 5:
    print("Count is:", count)
    count += 1  # Increment count by 1

A while loop can become an infinite loop if the condition never becomes False. You need to be careful to include a condition that will eventually break the loop.

while True:
    print("This will run forever if not stopped!")

The for loop is used to iterate over a sequence (like a list, tuple, string, or range). It is most commonly used when the number of iterations is known beforehand.

for variable in sequence:
    # Code to execute for each element in the sequence

for i in range(5):
    print("Value of i:", i)

print(list(range(5)))        # Output: [0, 1, 2, 3, 4]
print(list(range(2, 7)))     # Output: [2, 3, 4, 5, 6]
print(list(range(1, 10, 2))) # Output: [1, 3, 5, 7, 9]

A loop inside another loop is called a nested loop. The inner loop runs completely whenever the outer loop runs once.

for i in range(1, 4):
    for j in range(1, 4):
        print(f"i={i}, j={j}")

i=1, j=1
i=1, j=2
i=1, j=3
i=2, j=1
...

for i in range(5):
    if i == 3:
        break
    print(i)
# Output: 0 1 2

for i in range(5):
    if i == 3:
        continue
    print(i)
# Output: 0 1 2 4

for i in range(5):
    if i == 3:
        pass  # Placeholder, does nothing
    print(i)
# Output: 0 1 2 3 4

for i in range(5):
    print(i)
else:
    print("Loop completed successfully.")

count = 0
while count < 5:
    print(count)
    count += 1
else:
    print("Loop completed successfully.")

Write a Python program to find the sum of the first N natural numbers using a while loop.

Write a Python program to print the multiplication table of a given number using a for loop.

Given a list of numbers, write a Python program to print each number in the list using a for loop.

Write a Python program to calculate the factorial of a number using a while loop.

Write a Python program that takes an integer as input and checks whether it is a prime number or not using a for loop.

Write a Python program to print the following pattern using nested loops:

*
* *
* * *
* * * *
* * * * *

Write a Python program to generate the first N Fibonacci numbers using a while loop.

Write a Python program that takes a list of numbers and counts the number of even and odd numbers using a for loop and if condition

Enhance the "Guess the Number" game (from previous days) to provide a limited number of attempts (e.g., 5 attempts). After each wrong guess, inform the user of the remaining attempts.

Write a Python program that takes an input number n and prints an n x n multiplication table using nested loops

A list is a versatile, ordered collection in Python that can store a sequence of items. Lists are mutable, meaning their contents can be changed after they are created.

my_list = [item1, item2, item3, ...]

fruits = ["apple", "banana", "cherry"]
print(fruits)  # Output: ['apple', 'banana', 'cherry']

Indexing: Access individual elements in a list using their index (starting from 0).

fruits = ["apple", "banana", "cherry"]
print(fruits[0])  # Output: apple

Slicing: Access a subset of elements using a range of indices.

print(fruits[0:2])  # Output: ['apple', 'banana']

numbers = [3, 1, 4, 1, 5, 9]
numbers.append(2)
print(numbers)  # Output: [3, 1, 4, 1, 5, 9, 2]

numbers.sort()
print(numbers)  # Output: [1, 1, 2, 3, 4, 5, 9]

numbers.pop()
print(numbers)  # Output: [1, 1, 2, 3, 4, 5]

List comprehensions provide a concise way to create lists. It can be used to apply an expression to each item in an iterable.

new_list = [expression for item in iterable if condition]

squares = [x**2 for x in range(10)]
print(squares)  # Output: [0, 1, 4, 9, 16, 25, 36, 49, 64, 81]

A nested list is a list that contains another list as its element.

matrix = [
    [1, 2, 3],
    [4, 5, 6],
    [7, 8, 9]
]
print(matrix[1])      # Output: [4, 5, 6]
print(matrix[1][1])   # Output: 5

A tuple is similar to a list but is immutable, meaning it cannot be modified after creation. Tuples are used for fixed collections of items.

my_tuple = (item1, item2, item3, ...)

colors = ("red", "green", "blue")
print(colors)  # Output: ('red', 'green', 'blue')

Like lists, tuples can be indexed and sliced.

print(colors[0])    # Output: red
print(colors[0:2])  # Output: ('red', 'green')

t = (1, 2, 3, 1, 2)
print(t.count(1))  # Output: 2
print(t.index(3))  # Output: 2