What is a while loop in Python?

A while loop is used to execute a block of code repeatedly as long as a specified condition is True.

Syntax:

while condition:
    # code block to execute

• The condition is checked before each iteration.
• If the condition is True, the code block runs.
• If the condition becomes False, the loop stops.

Basic Example

count = 1

while count <= 5:
    print("Count is:", count)
    count += 1  # increase count by 1

Output:

Count is: 1
Count is: 2
Count is: 3
Count is: 4
Count is: 5

Explanation:

• The loop runs as long as count <= 5.
• count is increased by 1 each time.
• When count becomes 6, the condition is False, and the loop ends.

Infinite Loop Example

If the condition never becomes False, the loop runs forever:

while True:
    print("This will run forever!")

To avoid this, you can use a break statement or make sure the condition eventually becomes False.

Using break in a while Loop

while True:
    user_input = input("Enter 'exit' to stop: ")
    if user_input == "exit":
        break
    print("You entered:", user_input)

This loop keeps running until the user types "exit".

➰ Using continue in a while Loop

The continue statement skips the current iteration and goes to the next one.

num = 0

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

Output:

1
2
4
5

Explanation:

• When num is 3, continue skips the print(num) and moves to the next loop.

Summary

• while loops are great when you don't know in advance how many times to repeat.
• Always make sure the condition will eventually become False to avoid infinite loops.
• Use break to exit early and continue to skip an iteration.