Python While Loops – Repeat Until You’re Done!

⏱ 5 min read · Skill: Beginner

Last Updated: September 2025

Sometimes you want Python to keep doing something until a condition is no longer true — that’s when a while loop becomes your best friend! It’s super helpful when you don’t know in advance how many times you need to repeat something.

What’s a While Loop?

A while loop keeps running as long as a condition stays true. Once the condition becomes false, Python stops the loop. This makes it perfect for situations where you’re waiting for something to happen!

Example 1: Counting Up

i = 1
while i <= 5:
    print(i)
    i += 1
    

🔹Here, the loop keeps counting from 1 to 5. Don’t forget to update the value inside the loop, or it could go on forever!

Example 2: Asking for Correct Input

password = ""
while password != "python123":
    password = input("Enter the password: ")
print("Access granted!")
    

🔹The loop keeps asking until you enter the correct password. Perfect for making programs interactive!

Example 3: Using break to Exit Early

i = 0
while True:
    print(i)
    i += 1
    if i == 3:
        break
    

🔹break lets you stop the loop even if the condition hasn’t turned false yet. This way you can exit early when needed!

Example 4: Skipping Iterations with continue

i = 0
while i < 5:
    i += 1
    if i == 3:
        continue
    print(i)
    

🔹This loop skips printing the number 3 and continues with the next iteration — neat for filtering unwanted cases!

Example 5: Loops with Else

i = 1
while i <= 3:
    print(i)
    i += 1
else:
    print("Loop finished!")
    

🔹You can attach else to a while loop to run code after it completes. Great for final messages or cleanup!

Why Learn While Loops?

• They help you run code repeatedly when you don’t know how many times ahead of time.
• Useful for input validation, waiting for events, and more.
• Every interactive Python program uses loops like this!

Common Errors to Watch Out For

• Forgetting to update the condition: If the condition never changes, the loop will run forever!
• Using = instead of ==: One is for assigning, the other for checking equality—don’t mix them up!
• Infinite loops without break: A loop that never ends can freeze your program. Always plan an exit!

Practice Challenge

Create a program that keeps asking for your favorite fruit until you type “stop”. Use a while loop and print a fun message each time!