Python While Loop

The while loop in Python is used to repeatedly execute a block of code as long as the given condition is true. Once the condition evaluates to false, the loop stops, and the control moves to the next statement after the loop.

What is a While Loop?

A while loop runs as long as a specified condition is true. The loop will check the condition before each iteration, and if it is true, it executes the block of code inside the loop. If the condition is false initially, the code inside the loop will not execute.

Syntax of While Loop

Syntax


while condition:
    # Code block to execute

Explanation:

In this syntax:

1 : Print numbers from 1 to 5


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

Output

1 2 3 4 5

In this example, the while loop checks if the counter variable is less than or equal to 5. If the condition is true, it prints the current value of counter and then increments it by 1. The loop continues until counter becomes greater than 5.

Using While Loop with Break

You can use the break statement inside a while loop to terminate the loop prematurely, even if the condition is still true. The loop will stop when the break statement is encountered.

Syntax of Break

Syntax


while condition:
    if some_condition:
        break
    # Code block to execute

Example: Stop the loop when counter reaches 3


counter = 1
while counter <= 5:
    if counter == 3:
        break
    print(counter)
    counter += 1

Output

1 2

In this example, the while loop checks if counter is less than or equal to 5. If the counter is 3, the break statement is executed, causing the loop to terminate. The numbers 1 and 2 are printed before the loop breaks.

Using While Loop with Continue

You can use the continue statement to skip the current iteration of the loop and continue with the next iteration. When continue is encountered, the code following it is skipped, and the loop condition is checked again.

Syntax of Continue

Syntax


while condition:
    if some_condition:
        continue
    # Code block to execute

Example: Skip the current iteration when counter is 3


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

Output

1 2 4 5

In this example, the loop prints numbers from 1 to 5 but skips 3 due to the continue statement. When counter == 3, the continue skips printing 3 and goes to the next iteration.

Best Practices for Using While Loops