Khalid Ahmad Khattak

Lesson 8 – Loops (while & for)

Loops allow your program to repeat actions automatically. Instead of writing the same line many times, you can use a loop to perform the task efficiently. Python provides two main types of loops: while loops and for loops.

What Is a While Loop?

A while loop repeats as long as its condition is true. You must update the variable inside the loop; otherwise, it will run forever.

Example 1: Counting from 1 to 5

i = 1

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

Output:

1
2
3
4
5
        

Explanation:

The loop continues because i <= 5 is true. Each time the loop runs, i increases by 1.

What Is a For Loop?

A for loop repeats a block of code a specific number of times. It is commonly used with range() or with lists.

Example 2: Counting using a for loop

for i in range(1, 6):
    print(i)
        

Output:

1
2
3
4
5
        

Explanation:

range(1, 6) generates numbers 1 to 5. The loop runs once for each value.

Looping Through a List

You can use a for loop to process each item inside a list.

Example 3: Printing fruit names

fruits = ["apple", "banana", "mango"]

for item in fruits:
    print(item)
        

Output:

apple
banana
mango
        

Quiz: Test Your Understanding

for i in range(3):
    print("Hi")