🔁 Python Course in 4 to 6 Weeks – Lesson 7: Loops in Python (for, while)
Welcome to Lesson 7 of the Python Course in 4 to 6 Weeks! In this lesson, you'll learn how to automate repetitive actions using Python's two main types of loops: for
and while
. Loops are essential for reducing code repetition and handling data collections.
✅ What You'll Learn
- When and why to use loops
- The
for
loop structure and syntax - The
while
loop and control flow - Loop control keywords:
break
,continue
,pass
- Real-world examples and challenges
🔁 The for
Loop
Used to iterate over a sequence (like a list, tuple, or string):
fruits = ["apple", "banana", "cherry"]
for fruit in fruits:
print(fruit)
🔄 The while
Loop
Repeats a block of code while a condition is True
:
count = 0
while count < 5:
print("Count:", count)
count += 1
⚙️ Loop Control Statements
break
: Exit the loop completelycontinue
: Skip to the next iterationpass
: Do nothing (used as a placeholder)
for i in range(5):
if i == 3:
continue # Skips printing 3
print(i)
📏 The range()
Function
Commonly used with for
loops to repeat actions:
for i in range(1, 6):
print("Hello", i)
⚠️ Common Mistakes
- ❌ Infinite loops with
while
by forgetting to update the condition - ❌ Using incorrect indentation inside loop blocks
- ❌ Off-by-one errors in
range()
🧪 Practice Challenge
Create a Python file named multiples_finder.py
that:
- Asks the user for a number
- Prints all multiples of that number up to 100 using a loop
📥 Tools You'll Need
- 🐍 Python: https://www.python.org/downloads/
- 📝 VS Code: https://code.visualstudio.com/
- 🌐 Replit: https://replit.com/languages/python3
📌 Final Words
Loops are the key to efficient and dynamic programs. With for
and while
, you can repeat tasks, process data, and build interactive programs. Up next, we’ll explore one of Python’s most flexible data structures: lists and tuples.
🔗 Coming Next:
Lesson 8: Lists & Tuples – Working with Sequences 📦