Course Content

While Loops In Python

In the previous tutorial we discussed about loops in general, what they are and their benefits, why should we use them, along with syntax, and working for “for” loop. If you haven’t gone through that tutorial till now I will recommend you to go through that first so it will be easier for you to learn the concept of while loop, once you have the concept, what loops generally are.

Now as we know now what loops are and why they are used, in this section, I will go directly towards the working and syntax of while loop along with its comparison with for loop and where to use it.

“A while loop in python runs a bunch of code or statements again and again until the given condition is true when the condition becomes false, the loop terminates its repetition.”

The syntax for while loop is simple and very much like for loop. We have to use the keyword “while”, along with it we have to put a condition in parenthesis and after that, a colon is placed. The condition could be either true or false. Until the condition is true, the loop will keep on executing again and again. If we use a certain sort of condition in our while loop that, it never becomes false then the program will keep on running endlessly, until we stop it by force. So, this kind of mistake in our syntax is known as logical/human error.

To terminate an infinite loop, you can press Ctrl+C on your system.

For vs While:

A “for” statement loop runs until the iteration through, set, lists, tuple, etc. or a generator function is completed. In case of while loop the statement simply loops until the condition, we have provided becomes false. We generally use for loops for areas where we are already familiar with the number of iterations and use while loop where the number of iterations are unknown. Because while loop is solely based on the state of its condition.

 Let us understand the concept of the while loop and why we use it in areas where the number of iterations are not defined or we do not have any idea how many iterations would take place with the help of an example. Suppose that we have created an application for an ATM from where a customer can only withdraw money up to 5000 rupees. Now our condition in the while loop would be to iterate unless the input is between 1 to 5000. So, the condition will be true unless the user inputs a number between 1 to 5000, so the loop will iterate depending upon the time until the user submits the wrong input. The example is a bit rough, but I hope it helps you clear your concepts.

For a While loop to run endlessly we can pass true or 1 as a condition. 1 is also used in place of writing true as a whole. So, in this case, the condition will never become false so the program will run endlessly. But these kinds of programs do not output anything because they could never complete their execution.


amar_nath.9 1 year, 5 months ago
hi sir can how can I contact to you
purushisode 1 year, 2 months ago
bro why not provding discription i am using as node pls provide discrption
Vivek-Mishra 8 months, 2 weeks ago
Full Notes and Source Code ::::::::::} |::::::::::::| Thanks, Harry Bhai for Awesome Tutorials
udita2607 8 months, 1 week ago
Can u please also post theoretical notes


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