The next topic is the For Loop. The for loop in Python is used to iterate over a sequence (like a list, tuple, dictionary, set, or string) or other iterable objects. This loop allows us to execute a block of code multiple times based on the length of the sequence or specified range.
Below are 10 programs that demonstrate different uses of the For Loop in Python.
For Loop Programs
1. Print Numbers from 1 to 10
Description: This program uses a for loop to print numbers from 1 to 10.
# Program to print numbers from 1 to 10
for i in range(1, 11):
print(i)
2. Print Even Numbers within a Range
Description: Prints even numbers between 1 and 20 using a for loop with a step of 2.
# Program to print even numbers from 1 to 20
for i in range(2, 21, 2):
print(i)
3. Calculate the Sum of First N Natural Numbers
Description: This program calculates the sum of the first n natural numbers.
# Program to calculate the sum of first n natural numbers
n = int(input("Enter a number: "))
sum_n = 0
for i in range(1, n + 1):
sum_n += i
print("Sum of first", n, "natural numbers is:", sum_n)
4. Display Multiplication Table
Description: Displays the multiplication table of a number entered by the user.
# Program to display the multiplication table
num = int(input("Enter a number: "))
for i in range(1, 11):
print(f"{num} x {i} = {num * i}")
5. Print Each Character of a String
Description: Iterates over each character of a string and prints it on a new line.
# Program to print each character of a string
text = input("Enter a string: ")
for char in text:
print(char)
6. Find the Factorial of a Number
Description: Computes the factorial of a number using a for loop.
# Program to find the factorial of a number
num = int(input("Enter a number: "))
factorial = 1
for i in range(1, num + 1):
factorial *= i
print("Factorial of", num, "is:", factorial)
7. Calculate the Sum of Elements in a List
Description: This program calculates the sum of elements in a list using a for loop.
# Program to calculate the sum of elements in a list
numbers = [10, 20, 30, 40, 50]
sum_numbers = 0
for num in numbers:
sum_numbers += num
print("Sum of list elements:", sum_numbers)
8. Display Only Positive Numbers from a List
Description: Filters and displays only the positive numbers from a list of integers.
# Program to display only positive numbers from a list
numbers = [-10, 15, -30, 45, 0, 50]
for num in numbers:
if num > 0:
print(num)
9. Print Fibonacci Series up to N Terms
Description: Generates the Fibonacci series up to n terms.
# Program to print Fibonacci series up to n terms
n_terms = int(input("Enter the number of terms: "))
a, b = 0, 1
for i in range(n_terms):
print(a, end=" ")
a, b = b, a + b
10. Count Vowels in a String
Description: Counts and displays the number of vowels in a given string.
# Program to count vowels in a string
text = input("Enter a string: ")
vowels = "aeiouAEIOU"
count = 0
for char in text:
if char in vowels:
count += 1
print("Number of vowels:", count)
Explanation
Each For Loop program showcases different ways to use for loops to iterate over numbers, lists, and strings. The for loop structure is versatile and allows us to perform various operations based on the elements or indexes of the sequence, which makes it essential for performing repeated tasks.
The next topic is the While Loop. The while loop in Python repeatedly executes a block of code as long as the condition specified is True. This loop is useful when the number of iterations is not known beforehand, and we want the loop to continue until a certain condition is met.
Below are 10 programs that demonstrate different uses of the While Loop in Python.
While Loop Programs
1. Print Numbers from 1 to 10
Description: This program uses a while loop to print numbers from 1 to 10.
# Program to print numbers from 1 to 10 using while loop
i = 1
while i <= 10:
print(i)
i += 1
2. Sum of Natural Numbers
Description: Calculates the sum of first n natural numbers using a while loop.
# Program to calculate the sum of first n natural numbers using while loop
n = int(input("Enter a number: "))
sum_n = 0
i = 1
while i <= n:
sum_n += i
i += 1
print("Sum of first", n, "natural numbers is:", sum_n)
3. Print Even Numbers Between 1 and 20
Description: Prints even numbers between 1 and 20 using a while loop.
# Program to print even numbers from 1 to 20 using while loop
i = 2
while i <= 20:
print(i)
i += 2
4. Reverse a Number
Description: Reverses a number entered by the user using a while loop.
# Program to reverse a number using while loop
num = int(input("Enter a number: "))
reverse = 0
while num > 0:
digit = num % 10
reverse = reverse * 10 + digit
num = num // 10
print("Reversed number:", reverse)
5. Count Down from 10 to 1
Description: A countdown from 10 to 1 using a while loop.
# Program to count down from 10 to 1 using while loop
i = 10
while i > 0:
print(i)
i -= 1
6. Print Multiplication Table of a Number
Description: Prints the multiplication table of a number entered by the user.
# Program to print multiplication table using while loop
num = int(input("Enter a number: "))
i = 1
while i <= 10:
print(f"{num} x {i} = {num * i}")
i += 1
7. Check for Prime Number
Description: This program checks whether a number is prime using a while loop.
# Program to check if a number is prime using while loop
num = int(input("Enter a number: "))
i = 2
is_prime = True
while i <= num // 2:
if num % i == 0:
is_prime = False
break
i += 1
if is_prime and num > 1:
print(f"{num} is a prime number.")
else:
print(f"{num} is not a prime number.")
8. Factorial of a Number
Description: Calculates the factorial of a number using a while loop.
# Program to calculate factorial of a number using while loop
num = int(input("Enter a number: "))
factorial = 1
i = 1
while i <= num:
factorial *= i
i += 1
print(f"Factorial of {num} is {factorial}")
9. Find the Largest Number in a List
Description: Finds the largest number in a list using a while loop.
# Program to find the largest number in a list using while loop
numbers = [12, 54, 23, 89, 45, 77]
largest = numbers[0]
i = 1
while i < len(numbers):
if numbers[i] > largest:
largest = numbers[i]
i += 1
print("The largest number in the list is:", largest)
10. Guessing Game
Description: Implements a simple number guessing game where the user has to guess a random number.
# Program to implement a guessing game using while loop
import random
number_to_guess = random.randint(1, 100)
guess = None
attempts = 0
while guess != number_to_guess:
guess = int(input("Guess a number between 1 and 100: "))
attempts += 1
if guess < number_to_guess:
print("Too low! Try again.")
elif guess > number_to_guess:
print("Too high! Try again.")
else:
print(f"Congratulations! You've guessed the number in {attempts} attempts.")
Explanation
Each While Loop program demonstrates different use cases of the while loop. The while loop is ideal when we don’t know in advance how many times we need to repeat an operation and the loop continues as long as the specified condition remains True. These programs illustrate common scenarios such as counting, summing, reversing, and even implementing games.
The next topic is Nested Loops. A nested loop is a loop inside another loop. The inner loop is executed completely for each iteration of the outer loop. Nested loops are commonly used when you have a multi-dimensional data structure, like a matrix or a table, and need to iterate over each element within that structure.
Below are 10 programs that demonstrate different uses of Nested Loops in Python.
Nested Loop Programs
1. Print a Pattern of Stars (Right-Angled Triangle)
Description: Prints a right-angled triangle pattern of stars using nested loops.
# Program to print a right-angled triangle pattern using nested loops
n = int(input("Enter the number of rows: "))
for i in range(1, n + 1):
for j in range(i):
print("*", end="")
print() # new line after each row
2. Print a Square Pattern of Stars
Description: Prints a square pattern of stars using nested loops.
# Program to print a square pattern using nested loops
n = int(input("Enter the size of the square: "))
for i in range(n):
for j in range(n):
print("*", end="")
print() # new line after each row
3. Multiplication Table Using Nested Loops
Description: Prints the multiplication table for numbers 1 to 10 using nested loops.
# Program to print multiplication table using nested loops
for i in range(1, 11):
for j in range(1, 11):
print(f"{i} x {j} = {i * j}")
print() # new line after each table
4. Print a Pyramid Pattern of Stars
Description: Prints a pyramid pattern of stars using nested loops.
# Program to print a pyramid pattern using nested loops
n = int(input("Enter the number of rows for the pyramid: "))
for i in range(1, n + 1):
for j in range(n - i):
print(" ", end="") # spaces for alignment
for k in range(2 * i - 1):
print("*", end="") # stars in the pyramid
print() # new line after each row
5. Print a Number Pattern
Description: Prints a number pattern where each row contains numbers from 1 to the row number.
# Program to print a number pattern using nested loops
n = int(input("Enter the number of rows: "))
for i in range(1, n + 1):
for j in range(1, i + 1):
print(j, end="")
print() # new line after each row
6. Create a Multiplication Table in a Matrix Form
Description: Prints a multiplication table in a matrix form using nested loops.
# Program to create a multiplication table in matrix form
n = int(input("Enter the size of the table: "))
for i in range(1, n + 1):
for j in range(1, n + 1):
print(f"{i * j:3}", end=" ")
print() # new line after each row
7. Print a Hollow Square Pattern
Description: Prints a hollow square pattern using nested loops.
# Program to print a hollow square pattern using nested loops
n = int(input("Enter the size of the square: "))
for i in range(n):
for j in range(n):
if i == 0 or i == n - 1 or j == 0 or j == n - 1:
print("*", end="")
else:
print(" ", end="")
print() # new line after each row
8. Print Floyd’s Triangle
Description: Prints Floyd’s Triangle (a right-angle triangle filled with consecutive integers) using nested loops.
# Program to print Floyd's Triangle using nested loops
n = int(input("Enter the number of rows: "))
num = 1
for i in range(1, n + 1):
for j in range(1, i + 1):
print(num, end=" ")
num += 1
print() # new line after each row
9. Sum of Matrix Elements
Description: Calculates the sum of all elements in a 2D matrix using nested loops.
# Program to find the sum of elements in a matrix using nested loops
matrix = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]
sum_matrix = 0
for i in range(len(matrix)):
for j in range(len(matrix[i])):
sum_matrix += matrix[i][j]
print("Sum of matrix elements:", sum_matrix)
10. Print Diamond Pattern of Stars
Description: Prints a diamond pattern of stars using nested loops.
# Program to print diamond pattern using nested loops
n = int(input("Enter the number of rows for the upper half of the diamond: "))
# Upper half of the diamond
for i in range(1, n + 1):
for j in range(n - i):
print(" ", end="") # spaces for alignment
for k in range(2 * i - 1):
print("*", end="") # stars in the upper half
print() # new line after each row
# Lower half of the diamond
for i in range(n - 1, 0, -1):
for j in range(n - i):
print(" ", end="") # spaces for alignment
for k in range(2 * i - 1):
print("*", end="") # stars in the lower half
print() # new line after each row
Explanation
Each Nested Loop program demonstrates how to use loops inside loops to solve problems, print patterns, and manipulate data structures like matrices. Nested loops are essential for tasks like matrix traversal, generating complex patterns, or performing operations that require multiple levels of iteration.
Let me know if you’re ready to move on to the next topic, Pattern Programs!
