🔁 Understanding Loops in Python – A Complete Guide

Introduction 

Loops are fundamental in any programming language, and Python is no exception. They allow us to execute a block of code repeatedly, which is particularly useful for tasks involving iteration, automation, or repetitive calculations.

In this blog, we’ll explore the types of loops in Python, including:

for loops

while loops

nested loops

loop control statements (break, continue, and pass)

Each section comes with clean code examples and inline comments to illustrate their usage and expected output.

🧠 What Are Loops in Python?

A loop in Python is used to run a block of code multiple times. The primary two types are:

for loops – used for iterating over a sequence (like a list, tuple, dictionary, string, or range).

while loops – run as long as a condition is True.

🔂 1. for Loop in Python

The for loop iterates over a sequence (like a list or a string) and executes the block of code for each item.

Example 1: Iterating over a list

fruits = ["apple", "banana", "cherry"]

for fruit in fruits:

    print(fruit)

# Output:

# apple

# banana

# cherry

Example 2: Using range() with for loop

for i in range(5):

    print(i)

# Output:

# 0

# 1

# 2

# 3

# 4

🔁 2. while Loop in Python

A while loop repeats a block of code as long as a condition is True.

Example: Counting from 1 to 5

i = 1

while i <= 5:

    print(i)

    i += 1

# Output:

# 1

# 2

# 3

# 4

# 5

🔀 3. Nested Loops

A nested loop is a loop inside another loop. The inner loop completes all its iterations for every single iteration of the outer loop.

Example: Multiplication table using nested loops

for i in range(1, 4):

    for j in range(1, 4):

        print(i * j, end=" ")

    print()

# Output:

# 1 2 3

# 2 4 6

# 3 6 9

🧪 4. Loop Control Statements

Python provides several control statements to change the flow of loops:

4.1 break Statement

Stops the loop prematurely when a condition is met.

for i in range(10):

    if i == 5:

        break

    print(i)

# Output:

# 0

# 1

# 2

# 3

# 4

4.2 continue Statement

Skips the current iteration and moves to the next one.

for i in range(5):

    if i == 2:

        continue

    print(i)

# Output:

# 0

# 1

# 3

# 4

4.3 pass Statement

A placeholder that does nothing — used when a statement is syntactically required but you don’t want to execute any code.

for i in range(3):

    pass # Placeholder for future code

print("Loop executed with pass")

# Output:

# Loop executed with pass

📌 Conclusion

Loops are a crucial part of any Python programmer’s toolkit. Whether you're reading files, processing lists, or building algorithms, understanding how and when to use different types of loops — and controlling them with break, continue, and pass — is essential.

Keep practicing with your own examples and try using loops in small projects like:

Number guessing games

Basic calculators

Pattern generators (stars, pyramids)