In this Python tutorial, we will learn about While Loop statement, its syntax, and how to use this looping statement to execute a block of code repeatedly based on a condition, covering some example programs.
Python – While Loop
Python While Loop is used to execute a set of statements repeatedly based on the result of a condition.
When condition is True, the set of statements are executed, and when the condition is False, the loop is broken and the program control continues with the rest of the statements in program.
The syntax of Python While Loop is
while condition : statement(s)
The statement(s) are executed repeatedly in loop, as long as the condition is True. The condition is a boolean expression that should return or atleast implicitly typecast to boolean value.
The following is a flowchart to the flow of execution of While Loop. The loop is depicted in blue lines.
1. While Loop Statement to Print Multiples of 3
In the following program, we have a while loop statement that prints multiples of 3 in the range of 3 to 30.
i=1 while i < 11: print(3*i) i=i+1Try Online
3 6 9 12 15 18 21 24 27 30
Nested While Loop
1. Print Start Pattern using Nested While Loop
In the following example, we will write a while loop statement inside another while loop. Its like while in while which is nested while loop. Using this nested while loop, we print a start pattern.
i=1 while i < 11: j = 0 while j < i: print('*',end='') j=j+1 print() i=i+1Try Online
* ** *** **** ***** ****** ******* ******** ********* **********
More about Python Nested While Loop.
While Loop with Break
Python Break statement can be used inside a looping statement to break the loop even before condition becomes False.
In the following example, we have a while loop statement. The while loop has a break statements that executes conditionally when
i becomes 7. And inside this if-statement we have break statement. This break statement breaks the while loop.
i = 1 while i <= 100 : print(i) if i == 7 : break i += 1Try Online
1 2 3 4 5 6 7
More about Python While Loop with Break Statement.
While Loop with Continue
Python Continue statement can be used to skip the execution of further statements in while loop body and continue with next iteration of while loop.
In this example, we shall write a Python program with while loop to print numbers from 1 to 20. But, when we get an odd number, we will continue the loop with next iterations.
i = 0 while i <= 20 : i += 1 if i % 2 == 1 : continue print(i)Try Online
Make sure that you update the control variables participating in the while loop condition, before you execute the continue statement.
2 4 6 8 10 12 14 16 18 20
More about Python While Loop with Continue Statement.
Infinite While Loop
Infinite while loop is a loop in which the condition is always True and never comes out of the loop.
while True: print("hello")Try Online
hello hello hello hello
More about Python Infinite While Loop.
Python Programs based on While Loop
Following are references to some of the tutorials that use while loop in different scenarios.
In this Python Tutorial, we learned what a while loop is, its syntax, working mechanism of While loop, nested while loop and much more with examples.