Loops in Python

Python

Learn Python Programming: A Beginner’s Guide to Coding, Automation, and Data Science

 

What are Loops? 

Loops in Python help you repeat actions without writing the same code over and over again. Imagine if you had to write "Hello!" 100 times—loops save you from that nightmare! 

Python has two main types of loops:

Loop Type	Meaning
for loop	Repeats a block of code a specific number of times
while loop	Repeats a block of code as long as a condition is True

The for Loop 

Use a for loop when you know exactly how many times you need to repeat something.

for i in range(5):  # Loops 5 times (0 to 4)
    print(f"Iteration {i} ")

Real-life Example:

• You have a box of chocolates  and want to eat one at a time.

chocolates = ["Snickers", "Twix", "KitKat"]
for chocolate in chocolates:
    print(f"Eating {chocolate} ")

The while Loop 

Use a while loop when you don’t know exactly how many times to repeat, but you have a condition to check.

count = 0
while count < 5:
    print(f"Counting... {count} 📊")
    count += 1  # Don’t forget this! Or your loop will run forever 

Real-life Example:

• Keep eating  until you’re full!

hungry = True
slices = 5

while hungry and slices > 0:
    print("Eating a slice")
    slices -= 1
    if slices == 0:
        hungry = False
print("No more pizza!")

Loop Control Statements 

Sometimes, you need to control how your loop behaves. Python provides:

Statement	Meaning
break	Stops the loop immediately
continue	Skips the rest of the code and goes to the next iteration
pass	Does nothing (useful as a placeholder)

for number in range(10):
    if number == 5:
        break  # Stops the loop at 5
    print(number)

for number in range(10):
    if number % 2 == 0:
        continue  # Skips even numbers
    print(number)

Nested Loops 

Loops inside loops—loop-ception! 

for i in range(3):
    for j in range(2):
        print(f"Outer loop {i}, Inner loop {j}")

Real-life Example:

• Imagine a cafeteria with 3 tables, and each table has 2 chairs. You want to check every chair.

tables = 3
chairs_per_table = 2

for table in range(1, tables + 1):
    for chair in range(1, chairs_per_table + 1):
        print(f"Checking Table {table}, Chair {chair}")

Summary

Loop Type	Purpose
for loop	Use when you know how many times to loop
while loop	Use when looping until a condition is met
break	Stop the loop completely
continue	Skip the rest of the loop iteration
pass	Placeholder for future code
Nested loops	Loop inside a loop!

Now you're a looping master!  Keep practicing and write efficient Python code!