🔁 Loops in Python | Lesson 09

🔁 Loops in Python

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Loops help your program repeat tasks automatically without writing the same code again and again. They are perfect for when you want to process lots of data, run a task multiple times, or iterate over collections! Let’s dive into the magic of loops. ✨

What Are Loops? 🤔

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Loops execute a block of code multiple times until a condition is met or for every item in a collection.

1. The while Loop ⏳

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Repeats a block of code while a condition is true.

count = 1
while count <= 5:
    print("Count is", count)
    count += 1  # Increment count to avoid infinite loop

Important: Without changing the condition inside, a while loop can run forever (infinite loop).

2. The for Loop 🔄

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Used for iterating over a sequence (like list, string, or range).

colors = ["red", "green", "blue"]
for color in colors:
    print(color)

Often used with range() to repeat a fixed number of times:

for i in range(5):
    print("Iteration", i)

3. Loop Control Statements 🛑

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• break — Immediately stops the loop.
• continue — Skips the current iteration and moves to the next.
• else with loops — Runs when loop finishes without break.

for i in range(1, 6):
    if i == 3:
        continue  # Skip printing 3
    print(i)
else:
    print("Loop finished!")

Practice Questions with Solutions 🏆

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1. Practice: Print numbers from 1 to 10 using a while loop.
   • Solution:

num = 1
while num <= 10:
    print(num)
    num += 1

2. Practice: Print each character in the string “Python”.
   • Solution:

for ch in "Python":
    print(ch)

3. Practice: Use a loop to sum all numbers from 1 to 5.
   • Solution:

total = 0
for i in range(1, 6):
    total += i
print("Sum:", total)  # Output: 15

Step-by-Step Challenge: Guessing Game 🎯

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Ask the user to guess a secret number between 1 and 5 until they guess correctly.

secret = 3
guess = 0

while guess != secret:
    guess = int(input("Guess the number (1-5): "))
    if guess == secret:
        print("You guessed it right! 🎉")
    else:
        print("Try again!")

Checklist for This Chapter ✅

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• Used while loops to repeat with conditions
• Used for loops to iterate over sequences
• Controlled loops using break and continue
• Used else block in loops

You now have a powerful tool to automate repetitive tasks in Python. Keep practicing loops by creating games, calculators, and more! 🚀