# Python Tutorial - While Loop

Jinku Hu Jan 03, 2023 Feb 11, 2018 Python Python Loop

In this section, we will walk you through `while` loop that executes a number of statements for a specified number of times.

In a `while` loop, if the condition is `True`, control enters into the body of `while` and statements inside are executed. This process continues until the condition becomes `False`.

`while` loop is mostly used when you don’t know how many times the statements are going to be executed (total number of iterations).

The following is the syntax of Python `while` loop:

``````while condition:
block of statements
``````

Here, if the `condition` is `True`, control enters the body of `while` and the block of statements is executed. When the condition becomes `False`, the iteration will be stopped and the loop is terminated.

## `while` Loop Example

The following program calculates the sum of the first five even numbers:

``````sum = 0
i = 0			#initializing counter variable at 0
while i <= 10:
sum = sum + i
i = i + 2			#incrementing counter variable with inter of 2 for even numbers
print("Sum of the first five even numbers =", sum)
``````
``````Sum of the first five even numbers = 30
``````

Firstly, you need to initialize the value of your counter variable `i`. Then you have `while` loop containing a condition which tells that the loop should be terminated if `i` becomes greater than 10. Then counter variable `i` is incremented by adding 2 in each iteration which will generate even numbers as initially `i` was zero.

When `i` becomes 12, the loop is terminated and the `sum` is printed. In each iteration of the loop, the value of `i` is added to `sum`.

## `while` Loop With `else`

In a `while` loop, you can also have an `else` part which will be executed when the `condition` of `while` is evaluated to be `False`.

Note
If you use `break` to terminate the `while` loop, it will ignore the `else` part.
``````count = 0
while count < 4:
print("You are inside while loop")
count = count + 1
else:
print("You are in else part")
``````
``````You are inside while loop
You are inside while loop
You are inside while loop
You are inside while loop
You are in else part
``````

When `count` becomes greater than 4, `else` part is executed.

Author: Jinku Hu

Founder of DelftStack.com. Jinku has worked in the robotics and automotive industries for over 8 years. He sharpened his coding skills when he needed to do the automatic testing, data collection from remote servers and report creation from the endurance test. He is from an electrical/electronics engineering background but has expanded his interest to embedded electronics, embedded programming and front-/back-end programming.