In the nested-while loop in Python, Two type of while statements are available:Outer while loop; Inner while loop; Initially, Outer loop test expression is evaluated only once.. Loops iterate over a block of code until the test expression is false, but sometimes we wish to terminate the current iteration or even the whole loop without checking test expression. Let’s create a small program that executes a while loop. While True → Loop will run forever unless we stop it because the condition of while is always True.. We can stop it using break statement. You must be careful to change the counter in a while loop, or you’ll get an infinite loop. Leaving aside whether this loop is a good way to solve your larger problem, one reason your current while loop is not ever ending is because you've messed up the condition. A sentinel value denotes the end of a data set, but it is not part of the data. We can use break and continue statements with while loop. Great. Watch out for infinite loops when creating a program. Python has two primitive loop commands: while loops; for loops; The while Loop. Just like while loop, "For Loop" is also used to repeat the program. Python While Loops Previous Next Python Loops. In Python, while loops are constructed like so: while [a condition is True]: [do something] The something that is being done will continue to be executed until the condition that is being assessed is no longer true. Today you will learn about while loops with sentinel values. If you delete the line counter = counter + 1 from our while loop, it will run forever: it never goes above 0, so the indented code runs over and over again. Print i as long as i is less than 6: i = 1 while i 6: print(i) i += 1 How works nested while loop. The else block with while loop gets executed when the while loop terminates normally. The body starts with indentation and the first unindented line marks the end. Previously, you learned how to write loops that read and process a sequence of values. Now you know how while loops work, so let's dive into the code and see how you can write a while loop in Python. The condition is true, and again the while loop is executed. Sometimes you may want to use a ‘break’ statement to end the loop when a specific condition is met. Example. A loop that uses a sentinel value is called a sentinel-controlled loop. In Python, the body of the while loop is determined through indentation. This is the basic syntax: While Loop (Syntax) These are the main elements (in order): The while keyword (followed by a space). With the while loop we can execute a set of statements as long as a condition is true. In Python, break and continue statements can alter the flow of a normal loop. How to use "For Loop" In Python, "for loops" are called iterators. Flowchart of while Loop Flowchart for while loop in Python Example: Python while Loop While Loop. Python while loop is used to run a code block for specific number of times. If you already know the working of for Loop, then understanding the while Loop will be very easy for you. This continues till x becomes 4, and the while condition becomes false. Python interprets any non-zero value as True. the inner while loop executes to completion.However, when the test expression is false, the flow of control … When its return true, the flow of control jumps to the inner while loop. Python while Loop: In the previous article, we have briefly discussed the for Loop in Python.. Now, it’s time to move to the next and last type of Loop statement which is while Loop. But unlike while loop which depends on … To start, here is the structure of a while loop in Python: while condition is true: perform an action In the next section, you’ll see how to apply this structure in practice. None and 0 are interpreted as False. In this program, we’ll ask for the user to input a password. 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