Lesson 10 of 12

While Loops ⏳

🎯 Grades 6–8 ⏱ ~25 minutes 💚 Intermediate

What You'll Learn

  • Use while loops for unknown repetitions
  • Avoid infinite loops
  • Build a number guessing game

While vs For

A for loop is great when you know exactly how many times to repeat. A while loop keeps running as long as a condition stays True — useful when you do not know in advance how many times you need to loop.

Python
# Keep asking until a valid answer
password = ''
while password != 'opensesame':
    password = input('Enter the password: ')
print('Access granted!')

Counting with While

Python
count = 1
while count <= 5:
    print(f'Count: {count}')
    count += 1   # IMPORTANT: increment or loop runs forever!
print('Done!')
💡
Avoid Infinite Loops

Always make sure your while condition will eventually become False. If it never does, your program runs forever and freezes!

🎭">Guessing Game!

Pick a secret number (assign it to a variable). Use a while loop to keep asking the user to guess. Tell them Higher or Lower after each guess. Print how many tries it took!

Quick Check

When does a while loop stop?

AAfter 10 runs
BWhen you press stop
CWhen the condition becomes False

Why must you update the variable inside a while loop?

AFor speed
BTo print faster
CSo the condition eventually becomes False and the loop ends

Which loop is better when you do not know the number of iterations?

Afor loop
Bwhile loop
Crepeat loop
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