Python Loop Nesting Examples

One of the fundamental constructs in Python, and in programming in general, is the loop. Python offers two primary loop types: `for` and `while`. Understanding how to use and nest these loops effectively is crucial for solving a wide range of programming problems. In this article, we will delve into loop nesting in Python, explore their usage, and provide numerous examples to help you become proficient in harnessing the full potential of loops in your code.

1. The Basics of Looping in Python.

1. Before diving into loop nesting, let’s start with the basics of `for` and `while` loops in Python:

1.1 The `for` Loop.

1. The `for` loop in Python is used to iterate over a sequence (such as a list, tuple, string, or range) or any iterable object.
2. Here’s the basic syntax of a `for` loop:

   for element in iterable:
   # Code to execute for each element

3. Example:
   

   fruits = ["apple", "banana", "cherry"]
   for fruit in fruits:
       print(fruit)

4. Output:
   

   apple
   banana
   cherry

1.2 The `while` Loop.

1. The `while` loop, on the other hand, is used to repeatedly execute a block of code as long as a specified condition is true.
2. Here’s the basic syntax of a `while` loop:

   while condition:
   # Code to execute while the condition is true

3. Example:
   

   count = 0
   while count < 5:
       print(count)
       count += 1

4. Output:
   

   0
   1
   2
   3
   4

2. Nesting `for` Loops.

1. Loop nesting refers to placing one loop inside another.
2. This allows you to create complex and efficient algorithms for tasks that involve multidimensional data or require iterating through multiple sequences.
3. Let’s explore some examples of nested `for` loops:

2.1 Example 1: Multiplication Table.

1. Source code.

   for i in range(1, 6):
       for j in range(1, 6):
           print(i * j, end='\t')
       print()

2. Output:

   1       2       3       4       5
   2       4       6       8       10
   3       6       9       12      15
   4       8       12      16      20
   5       10      15      20      25

2.2 Example 2: Finding Prime Numbers.

1. Source code.

   for num in range(2, 101):
       is_prime = True
       for i in range(2, int(num**0.5) + 1):
           if num % i == 0:
               is_prime = False
               break
       if is_prime:
           print(num, end=' ')
   

2. Output:
   

   2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73 79 83 89 97

3. Nesting `while` Loops.

1. Just like `for` loops, `while` loops can also be nested to solve more complex problems.
2. Here are some examples:

3.1 Example 1: Printing a Triangle.

1. Source code.

   row = 1
   while row <= 5:
       col = 1
       while col <= row:
           print('*', end=' ')
           col += 1
       print()
       row += 1

2. Output:
   

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

3.2 Example 2: Fibonacci Series.

1. Source code.

   a, b = 0, 1
   while a < 100:
       print(a, end=' ')
       a, b = b, a + b

2. Output:
   

   0 1 1 2 3 5 8 13 21 34 55 89

4. Conclusion.

1. Loop nesting is a powerful technique in Python, enabling you to tackle a wide range of problems efficiently.
2. Whether you’re working with `for` loops or `while` loops, mastering the art of loop nesting will help you write more complex and sophisticated programs.
3. Use the examples provided in this article as a starting point, and explore further to unlock the full potential of loops in Python.
4. With practice and creativity, you’ll be able to tackle a variety of programming challenges with ease.